Download to read offline
![Theranostic nanostructures as
nanomedicines: benefits, costs,
and future challenges
1
Dickson Pius Wande1
, Natalie Trevaskis 2
, Muhammad Asim Farooq2
,
Amna Jabeen3
and Amit Kumar Nayak4
1
Department of Pharmaceutics and Pharmacy Practice, School of Pharmacy, Muhimbili
University of Health and Allied Sciences, Dar es Salaam, Tanzania; 2
Drug Delivery,
Disposition, and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash
University, Melbourne, VIC, Australia; 3
Faculty of Pharmacy, Lahore College of
Pharmaceutical Sciences, Lahore, Punjab, Pakistan; 4
Department of Pharmaceutics,
Seemanta Institute of Pharmaceutical Sciences, Jharpokharia, Mayurbhanj, Odisha, India
1.1 Introduction
Nanomedicine is a developing field merging nanoscience, nanoengineering, and nano-
technology with life sciences, revealing the valuable results for healthcare [1].
Although there are numerous nanomedicine applications, nanotechnology-based
drug delivery systems and nanoimaging agents are of the utmost interest in medicine
and pharmacy. “Theranostic” refers to the simultaneous integration of diagnosis and
therapy [2]. Theranostic nanomedicines (or nanotheranostics) combine the use of
theranostics with nanosized constructs that give multiple properties, such as targeted
drug delivery, controlled release, greater transport efficiency via endocytosis,
stimuli-responsive systems, and the amalgamation of therapeutic approaches, such
as multimodality diagnosis and therapy [3]. Nanotheranostics unite the three stages
in a single process, supporting early-stage diagnosis and treatment to overcome
some of the issues with sensitivity and specificity of current medicines. An ideal nano-
theranostic system should circulate for a long time in the body, provide sufficient
release behavior, show tissue target specificity and penetration, imaging capability,
and high target to background ratio [4].
Recently, novel and promising nanotherapeutic applications in the diagnosis and
treatment have been revealed in various diseases, such as cancer [5,6]. However,
the development of novel tools with improved imaging characteristics, which can
lead to the early detection of diseases, is still of high importance. Aside from the ap-
plications for diagnosis and nanotherapeutics are being increasingly designed and
applied to treat a range of serious diseases [7]. At present, nanotheranostics are viewed
as one of the key upcoming new strategies to tackle cancer, based on the postulation
that if cancer progression can be hindered during an initial diagnostic procedure, the
consequent anticancer therapy would be much easier since cancer growth will be
Design and Applications of Theranostic Nanomedicines. https://doi.org/10.1016/B978-0-323-89953-6.00008-8
Copyright © 2023 Elsevier Ltd. All rights reserved.](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-16-2048.jpg)
![retarded and the overall cancer burden will be reduced [8,9]. The main challenge is to
develop a system for molecular therapy capable of circulating in the bloodstream un-
detected by the immune system of body and capable of recognizing the required target
and signaling for effective drug delivery or gene silencing. As a result, nanotechnology
plays a vital role in providing new types of nanotherapeutics for diseases that can pro-
vide effective treatments with negligible side effects and high specificity [10,11].
Generally, theranostic nanomedicines can be engineered in several ways using tech-
nologies, such as polymeric nanoparticles [12], carbon-based nanomaterials [13,14],
lipid-based nanovesicles [15,16], protein-based nanostructures [17], dendrimers
[18], ceramic nanostructures [19], metallic inorganic nanocarriers [20], and graphene
quantum dots [21].
1.2 Nanotechnology, nanoscale, and nanostructures
Nanoscale science and technology often referred to as “nanoscience” or “nanotech-
nology” are science and engineering carried out on the nanometer scale, that is,
10 9
m [22]. Nanotechnology is the field of research and innovation concerned with
building materials, devices, and systems on the scale of atoms and molecules [23].
The US National Nanotechnology Initiative states: “The essence of nanotechnology
is the ability to work at the molecular level, atom by atom, to create large structures
with the fundamentally new molecular organization” [24]. The purpose is to exploit
these properties by gaining control of structures and devices at atomic, molecular,
and supramolecular levels to learn how to manufacture and use these devices, effi-
ciently. The United States National Science Foundation defines nanoscience/nanotech-
nology as studies dealing with materials and systems displaying three key properties:
dimensiondat least one dimension from 1 to 100 nanometers (nm); processd
designed with methodologies that show fundamental control over the physical and
chemical attributes of molecular-scale structures; building block propertydthey can
be combined to form larger structures [23e25].
In a general sense, nanoscience is quite natural in microbiological sciences consid-
ering that the sizes of many bioparticles dealt with by the body (like enzymes, viruses,
etc.) fall within the nanometer range [24]. Several nanoscale technologies are now
available in the market. For example, specially prepared nanosized semiconductor
crystals (quantum dots) are used as a tool for the analysis of biological systems
[25]. Upon irradiation, these dots fluoresce specific colors of light based on their
size. Quantum dots of different sizes can be attached to different molecules in a bio-
logical reaction, allowing researchers to follow all the molecules simultaneously dur-
ing biological processes with only one screening tool. These quantum dots can also be
used as a screening tool for quicker, less laborious DNA and antibody screening than is
possible with more traditional methods [22,26].
Nanostructures can be categorized depending on their size, shape, composition, sur-
face characteristics, functionalization, and origin. The ability to predict the properties
of nanostructures based on their classification is very useful to their applications [27].
4 Design and Applications of Theranostic Nanomedicines](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-17-2048.jpg)
![In terms of shape, nanostructures can be classified into spherical, conical, spiral, cylin-
drical, tubular, flat, hollow, or irregular in shape and can be from 1 to 100 nm in size
[27,28]. Most nanostructured materials can be generally classified into four materials-
based categories (organic, inorganic, composite, and carbon-based) [29]. Among these
nanostructures, the use of a combination of more than one nanostructure to form a
hybrid-nanostructure system is not uncommon [30].
Hybrid nanostructures are carefully designed with a combination of different mate-
rials, which have different physiochemical properties and load different types of drugs.
Hybrid nanostructures can also encompass nanoparticles that contain both structural
(therapeutic) and functional (diagnostic) nanocomponents. The drug can be either
encapsulated or bound to the surface of nanostructures depending on the physicochem-
ical properties of the nanocarriers. These hybrid structures have a higher surface area.
They are often engineered to increase the drug loading capacity. Sometimes, nanocar-
riers can be designed to respond to specific endogenous or exogenous stimuli for
controlled drug release [25]. Targeted drug delivery can be monitored externally by
fluorescence dyes or intrinsic optical/magnetic/electrical properties of nanostructures.
The development of hybrid nanostructures signifies an important step toward an effi-
cient delivery of a range of therapeutics and imaging agents as hybrid nanostructures
may allow the delivery of a combination of multiple drugs, DNA, RNAs, and diag-
nostic agents [29].
1.2.1 Carbonaceous-based hybrid nanostructures
Carbon nanotubes are hydrophobic in nature and compromise the tubular nanostruc-
tures with diameters in the order of less than 50 nm [31,32]. They display remarkable
mechanical and optical properties [33,34]. These features have been harnessed in
biomedical applications, such as photodynamic therapy [35], diagnostic imaging
[36], and drug delivery [37].
Carbon nanotubes are essentially nontoxic, have high biocompatibility in the body,
and are excreted via renal or biliary pathways depending on their surface chemistry
[38]. They often have a longer blood circulation time than many other nanoparticles
[39]. Graphene is an allotrope of carbon composed of a hexagonal network of a
honey-comb structure made up of carbon atoms consisting of sp2-hybridized bonded
carbon on a 2D planar surface [40,41]. The thickness of a graphene sheet is about
1 nm. Fullerenes (C60) are carbon-based molecules and spherical in morphology
[42]. These are made up of carbon atoms held together via sp2
hybridization. Gener-
ally, the other fullerenes (0D), such as C76, C80, and C240, are synthesized from larger
numbers of carbon atoms [29]. Fullerenes are comprised of between 28 and 1500 car-
bon atoms that form spherical structures [43]. Single-layer fullerenes have diameters
up to 8.2 nm, while multilayer fullerenes have diameters between 4 and 36 nm.
1.2.2 Organic-based nanostructures
Dendrimers, liposomes, and polymeric micelles are usually known as organic nano-
structures [44]. These include nanostructures mostly made of organic materials. These
Theranostic nanostructures as nanomedicines: benefits, costs, and future challenges 5](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-18-2048.jpg)
![nanostructures are generally nontoxic and biodegradable in nature. Sometimes, these
are sensitive to electromagnetic and thermal radiation. Organic nanostructures are most
employed in pharmaceuticals for drug delivery systems because of their high biocom-
patibility [44,45]. Dendrimers are prepared from monomers by either convergent or
divergent step-growth polymerization [46]. The surface of a dendrimer encompasses
several chains that can be modified to accomplish specific and specialized biochemical
functions. Polymeric micelles possess amphiphilic block copolymers assembled to
form nanoscopic core-shell structures [47,48]. Both the intrinsic and modifiable prop-
erties of polymeric micelles make them well suited for the systemic delivery of poorly
water-soluble medicines.
1.2.3 Inorganic-based nanostructures
Inorganic nanostructures encompass structures that are not made from carbon-based
or organic-based systems. Inorganic-based nanostructures have been of particular
interest for bioimaging applications due to their high thermal conversion efficiency,
ease of synthesis, and possible surface modifications [49]. These nanostructures
include metal and metal oxide nanostructures. Metal-based and metal oxide-based
nanostructures are commonly categorized as inorganic nanostructures. These nano-
structures can be synthesized into metal nanostructures, such as palladium or gold,
metal oxide nanostructures like titanium dioxide, and semiconductors, such as ce-
ramics and silicon. Metal-based nanoparticles have fascinated scientists for over a
century and are nowadays heavily utilized in biomedical and material sciences.
Almost all metals can be synthesized into nanostructures or nanoparticles. Gener-
ally, aluminum (Al), gold (Au), silver (Ag), copper (Cu), cobalt (Co), cadmium
(Cd), lead (Pb), iron (Fe), and zinc (Zn) metals are used for nanostructure synthesis
[50e52]. Inorganic metal nanoparticles possess unique properties, such as large
surface areas, surface charge densities, pore sizes, and stability. These kinds of
nanoparticles can be cylindrical or spherical in shape, crystalline or amorphous
in structure, and typically less than 100 nm in size [53]. Metal oxide-based nano-
structures are synthesized mainly because of their increased efficiency and reac-
tivity. Metal oxide-based nanostructures are prepared in order to modify the
physicochemical properties of their respective metal-based nanostructures. The
most commonly used metal oxides for the synthesis of nanostructures that have
been well characterized include zinc oxide and iron oxide nanostructures
[54e56]. Iron oxide nanostructures have generated incredible interest in nanomedi-
cine due to their many beneficial properties [57]. Specifically, it has been found that
when iron oxide nanostructures are reduced to a size of 20 nm, they become
superparamagnetic in the presence of a magnetic field; as a result, they have
become very useful for applications, such as magnetic resonance imaging (MRI)
and targeted drug delivery and release [58e60].
6 Design and Applications of Theranostic Nanomedicines](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-19-2048.jpg)
![1.3 Design of theranostic nanostructures as
nanomedicines
Nanotheranostic agents can be engineered in several ways. For instance, therapeutic
agents (e.g., anticancer agents and photosensitizers) may be loaded into existing nano-
particles that enable imaging, such as quantum dots, iron oxide nanostructures, and
gold nanostructures. Another possibility is tagging of imaging contrast agents to the
existing therapeutic nanostructures. In addition, encapsulating both imaging and ther-
apeutic agents together in biocompatible nanostructures can be effective [61]. Finally,
the engineering of unique nanostructures with intrinsic imaging and therapeutic prop-
erties may yield beneficial results. The conceptual design of nanotheranostics has been
broadly categorized in the literature [62e65]. Based on the classification by Ferrari
[66], nanotheranostics can be dichotomized into three components, namely, biomed-
ical payload, carriers, and surface modifiers (e.g., polyethylene glycol, dextran, poly-
peptides), subject to their roles and their physical locations.
1.3.1 Therapeutic pay-loads
1.3.1.1 Therapeutics
The therapy type most commonly delivered in nanostructures is cancer chemothera-
peutics. Chemotherapy is the treatment of choice for most cancer cases, but drug
toxicity, poor absorption to the tumor site, and multidrug resistance limit therapy
[67]. Cancer cells differ from normal cells in that they usually grow faster and in an
uncontrolled manner and show malignant behaviors like metastasis. The observed un-
controlled and fast growth rates are empowered by fast DNA synthesis. Chemothera-
peutic drugs act by interfering with the synthesis and function of DNA to halt cell
divisions by specifically targeting the fast-dividing cells, ultimately leading to inhibi-
tion of tumor growth and metastasis [68]. In order to vanquish the toxicity of chemo-
therapeutics drugs, nanomedicine developments have emerged with theranostics
nanostructure-based drug delivery systems. Nanostructure-based drug delivery sys-
tems have great potential to lower cytotoxicity and enhance the therapeutic efficiency
of anticancer drugs [69]. They can be engineered to target specific surface receptors on
cancer cells, thus, facilitating targeted delivery [70]. In order to reduce the side effects
of chemotherapeutic drugs on the normal healthy tissues, nanostructure-based drug de-
livery treatments are required to realize higher efficacy with insignificant side effects.
Nevertheless, theranostic nanostructure-based systems must be biodegradable and
ideally display long systemic circulation half-life and targeted delivery into the specific
tissue [71].
Nanostructure-based drug delivery systems can be tailor-made to selectively deliver
drugs to the cancerous sites and reducing the chances of unspecific delivery to the non-
cancerous tissues, thus, reducing the side effects of the chemotherapeutic agents [72,73].
Theranostic nanostructures as nanomedicines: benefits, costs, and future challenges 7](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-20-2048.jpg)
![Hence, theranostic nanostructure-based drug delivery has the greatest potential for futur-
istic applications for improved treatments of most diseases, including cancer.
1.3.1.2 Imaging
There are several imaging modalities that can be integrated into nanotheranostics sys-
tems. Herein, we discuss only the commonly used modalities such as optical imaging,
magnetic resonance imaging (MRI), computed tomography (CT), positron emission
tomography (PET), and single-photon emission computed tomography (SPECT).
Among these modalities, CT and MRI have been widely studied modalities for image
reconstruction due to low-dose CT and fast MRI repository. Nuclear imaging tech-
niques, such as PET and SPECT, are very useful for nanotheranostics application, pre-
dominantly due to high fidelity for detecting and characterize tumors before, during,
and after therapy with chemotherapy and immunotherapy [25,74]. The optical imaging
modality utilizes organic fluorescent dyes, such as fluorescein isothiocyanate (FITC) to
monitor molecular events in biological systems [75]. Visible or ultraviolet (UV) light
can be used to excite organic dyes. However, it does not penetrate deeply into tissues,
limiting the application of organic dyes mainly to the bioimaging of cells. In addition,
individual organic dyes are photo-bleachable and rather toxic. Consequently, methods
have been developed whereby organic dyes are protectively encapsulated into nano-
carriers, such as SiO2-matrices [76,77] or polymeric nanoparticles [78]. These have
been developed to provide the desired photostability and decrease loss during delivery,
resulting in lower imaging ability and increased toxicity.
Matrix metalloproteinases (MMPs) on tumor cells can be useful targets for tumor
imaging and treatment [79]. Typically, optical imaging probes are linked onto the ther-
apeutic nanostructure via MMP-breakable peptide linkers, and the optical probes are
“switched off” by a fluorescence resonance energy transfer (FRET) mechanism. The
optical imaging probes are released from the nanostructure upon reaching target tumor
cells, resulting in the fluorescence being “switched on” [79,80].
MRI is a noninvasive medical imaging tool to visualize detailed internal structures
[81,82]. For MRI, atoms in the body are aligned under a powerful magnetic field.
Radiofrequency fields change the alignment of the magnetization of atoms. This
causes the nuclei to produce a rotating magnetic field detectable by the scanner, which
can be recorded to construct an image of the body. Strong magnetic field gradients
cause nuclei at different locations to rotate at different speeds, thus providing 3D
spatial information. Compared with other medical imaging techniques, such as CT,
MRI provides good contrast between the different soft tissues of the body, which
makes it especially useful in imaging the brain, muscles, the heart, and cancers [83].
Another advantage of MRI is that it does not need to use ionizing radiation, damaging
cell structure. PEGylated paramagnetic and fluorescent Gd diethylene triamine penta-
acetic acid (DTPA)-bis(sterylamide) immunoliposomes are capable of detecting dese-
lecting expression level [84]. E-selectin, an endothelial cell surface receptor, is
imperative for pathophysiological and therapeutic responses, including avb3-integrins
and the VEGF receptor. Liposome particles were designed to bind to E-selectin over-
expressing HUVEC cells, and cell internalization was confirmed by boosting the T1-
weighted MRI signal.
8 Design and Applications of Theranostic Nanomedicines](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-21-2048.jpg)
![Regarding CT imaging, several studies have been conducted where chemothera-
peutics were loaded into gold nanostructures for visualization by CT imaging. Kim
et al. [85] reported a gold nanostructure for theranostic targeted molecular CT imaging
and prostate cancer therapy. For targeting, the surface of gold nanostructure was deco-
rated with a prostate-specific membrane antigen (PSMA) bound with RNA aptamer.
In vitro experiments showed that the PSMA aptamer-conjugated gold nanostructure
instigated at least a fourfold raise in CT intensity for a targeted LNCaP cell than
that of a nontargeted PC3 cell. Furthermore, after loading the targeted gold nanostruc-
ture with doxorubicin (DOX), drug release experiments showed that approximately
35% of DOX was released within 1 h. The particle potency against targeted LNCaP
cells was significantly higher than against nontargeted PC3 cells. Another multifunc-
tional theranostic gold nanostructure for targeted CT imaging and drug delivery was
reported [86]. In this, dendrimer-entrapped gold nanostructure was covalently linked
with a-tocopheryl succinate (a-TOS), which possesses intrinsic anticancer activity
(a-TOS can induce apoptosis of various cancer cells), inhibit the cell cycle, and inter-
rupt signaling pathways of tumor growth but not affecting the proliferation of normal
cells [2].
PET and SPECT are both imaging techniques that utilize g-rays emanating from the
decay of radioactive sources inside the body. Consequently, these modalities require
the administration of radio-nuclides to generate the signal for image construction
[87]. These imaging modalities offer several advantages: higher sensitivity, noninva-
siveness, little background noise, and the generation of three-dimensional images in a
real-time manner. PET is more sensitive than SPECT and is often associated with other
techniques like CT to obtain anatomical contrast [88]. Nanostructures can provide an
excellent platform for the attachment of radioisotopes for nanotheranostics applica-
tions (i.e., early diagnosis of diseases and combining in vivo imaging and drug deliv-
ery. Furthermore, using radiolabeled nanoparticles enhances the accumulation of the
radioisotopes in the tumor by EPR effect, reducing the number of these agents in
nontarget tissues, generating an even higher sensitivity to the techniques [87].
1.3.2 Nanocarriers
1.3.2.1 Polymeric nanoparticles and micelles
Polymers are among the most easy-handled and economical carriers due to their
important characteristics, such as biocompatibility, biodegradability, and stability
against degradation [1]. Both synthetic and natural macromolecules have been utilized
as nanotheranostics. However, they should be first modified to possess imaging ability
and therapeutic activity [89]. Sachdev and Matai [90] developed chitosan-based
hydrogel loaded with highly fluorescent carbon dots and anticancer drug, 5-
fluorouracil. The cross-sectional view demonstrated an irregular morphology with
highly porous and interconnected networks, indicating a typical of hydrogels. Carbon
dots were found as confined to be visualized by field emission-scanning electron mi-
croscopy (FE-SEM) (Fig. 1.1a). The occurrences of carbon dots in matrices of hydro-
gels could be clearly distinguished by transmission electron microscope (TEM)
Theranostic nanostructures as nanomedicines: benefits, costs, and future challenges 9](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-22-2048.jpg)
![micrographs, wherein numerous dark tiny domains of carbon dots produced a clear
contrast with the comparatively gray hydrogel matrix (Fig. 1.1b). High-resolution
TEM micrographs further demonstrated uniform distribution of carbon dots within
the hydrogel matrix (Fig. 1.1c). It was found out that the system was able to show
cellular uptake as well as therapeutic effects. In addition, in vitro studies exhibited
apoptosis in A549 cells. Manifestation of apoptosis in chitosan-based hydrogel loaded
with highly fluorescent carbon dots and 5-fluorouracil treated A549 cells was evi-
denced by FE-SEM images (Fig. 1.2). Treated A549 cells underwent shape change
and drastic shrinkage in comparison to that of untreated A549 cells. To sum up, the
green fluorescence of carbon dots could be used to detect apoptosis instigated by 5-
fluorouracil, eliminating the need for multiplex dyes. Other polymers have also been
employed as nanotheranostics.
1.3.2.2 Lipid nanovesicles
Liposomes are relatively stable, consist of structured biocompatible and biodegradable
lipid carriers; some liposomes have been approved by FDA [91]. In most cases, lipo-
somes are functionalized or coated with active molecules such as PEG, vitamins that
Figure 1.1 (a) FE-SEM (b) TEM and (c) High resolution TEM image of freeze-dried chitosan-
based hydrogel loaded with highly fluorescent carbon dots and 5-fluorouracil [90].
With permission, Copyright © 2016 Elsevier B.V.
Figure 1.2 FE-SEM micrographs of (a) untreated and (b) chitosan-based hydrogel loaded with
highly fluorescent carbon dots and 5-fluorouracil treated A549 cells after 48 h incubation [90].
With permission, Copyright © 2016 Elsevier B.V.
10 Design and Applications of Theranostic Nanomedicines](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-23-2048.jpg)
![can induce their biocompatibility. For example, vitamin E TPGS-coated liposomes are
widely prepared [92]. In further, PEG-coated and folate-PEG-coated long-circulating
and pH-sensitive liposomes loaded with 159
Gd and poly-L-lysine (159
Gd-SpHL and
159
Gd-FTSpHL, respectively) were studied as cancer nanotheranostics [93]. The pre-
pared liposomes provide increased animal survival and high tumor uptake. Scinti-
graphic photographs obtained at 1, 4, 6, and 8 h after intravenous (i.v.)
administration of PEG-coated and folate-PEG-coated long-circulating pH-sensitive li-
posomes loaded with 159
Gd and poly-L-lysine (159
Gd-SpHL and 159
Gd-FTSpHL,
respectively) are shown in Fig. 1.3. The advanced theranostic liposomes are conju-
gated with molecular biomarkers for targeting effect. To overcome opsonization by
the immune system and fast elimination from blood circulation, stealth liposomes,
i.e., PEG-coated liposomes, were formulated with stability and a longer half-life in
blood [94].
1.3.2.3 Dendrimers
Dendrimers are synthetic nanomedicine that comprises a highly branched spherical
polymer. These are used in nanotheranostics are typically less than 100 nm [95].
The higher generation dendrimers resemble the spherical shape, having a number of
cavities and branches capable of encapsulating both therapeutic agents and diagnostic
agents for nanotheranostics applications. The fifth generation of dendrimers displays
more hydrophobicity. It is generally preferred owing to enhanced encapsulation
Figure 1.3 Scintigraphic photographs obtained at 1, 4, 6, and 8 h after I.V. administration of
PEG-coated and folate-PEG-coated long-circulating and pH-sensitive liposomes loaded with
159
Gd and poly-L-lysine (159
Gd-SpHL and 159
Gd-FTSpHL, respectively); Arrows indicate
tumor site [93].
With permission, Copyright © 2015 Elsevier B.V.
Theranostic nanostructures as nanomedicines: benefits, costs, and future challenges 11](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-24-2048.jpg)
![efficiency and stability of guest molecules (i.e., drug and diagnostic agent) in a den-
dritic matrix [96,97].
1.3.2.4 Protein-based nanostructures
Proteins, mostly therapeutic proteins, have been developed to treat various diseases,
including cancer, infections, and genetic disorders [98]. Recently, protein-based bio-
materials with eminent biocompatibility have shown widespread potential applications
in nanotheranostics. Fluorescent proteins and proteins labeled with fluorescent dyes
can be simply traced under in vivo fluorescence imaging. Notably, in vivo imaging us-
ing fluorescent antibodies has been used for theranostic applications (i.e., imaging,
diagnosis, and predicting therapeutic responses) [98].
1.3.2.5 Metallic nanostructures
Several metallic nanostructures have extensively been investigated for nanotheranos-
tics applications [99,100]. Among metallic nanostructures that have been studied,
gold, and iron have shown fascinated results. Gold nanostructures based on gold cores
are prepared with a small core size from 1.5 to 10 nm, providing a large area for effi-
cient drug and ligand conjugations [101]. The chemical treatment of hydrogen tetra-
chloroaurate generally manufactures gold nanostructures. Gold nanostructures can
be conjugated with drug and targeting ligand as advanced nanotheranostics that spe-
cifically recognizes the target receptor for active targeting [102]. Drug loading can
be achieved by either electrostatic interaction or covalent chemical conjugation,
depending on the nature of the parent drug. The inherent features of gold nanostruc-
tures include diagnostic property, tunable core size, low toxicity, large surface to vol-
ume ratio, surface plasmon absorption, light-scattering properties, and ease of
synthesis [102,103].
Metallic magnetic nanostructures (MNS) have especially attracted considerable
attention from scientists for addressing cancer nanotheranostics [104,105]. The diag-
nostics potential of MNS arises from their role in enhancing the contrast in MRI.
The therapeutic prospects of MNS stem from thermal activation under externally
applied radio frequency (RF) field and localized release of therapeutic cargo [104].
Fe3O4 MNS are extensively used in nanotheranostics because of their biocompatibility
and ease of synthesis. The magnetic moment (which influences MRI fidelity) of super-
paramagnetic Fe3O4 MNS is dependent on the size of smaller particles producing
lower magnetic moments [102]. MRI-based immune cell tracing using MNS has
been applied to several biological studies, such as tumor targeting of cytotoxic
T cells and natural killer cells [104].
1.3.2.6 Ceramic nanostructures
Ceramic nanostructures or nanoceramics are emerging as a novel platform for nano
theranostics applications mainly due to their small size (50 nm) and physicochemical
properties. They include particles made from silica, iron oxide, or aluminum [106].
Mesoporous silica nanoparticles (MSNs) are promising functional nanostructures for
12 Design and Applications of Theranostic Nanomedicines](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-25-2048.jpg)
![various nanotheranostics applications (such as bioimaging, drug/gene delivery, and
cancer therapy). This is due to their low density, low toxicity, high biocompatibility,
large specific surface areas, and excellent thermal and mechanical stability. Aluminum
oxide (Al2O3) ceramic nanostructures have also been used for nanotheranostics appli-
cations; these ceramic nanostructures are not vulnerable to swelling or changes in
porosity with pH [107]. Furthermore, ceramic nanostructures can protect different bio-
macromolecules, such as enzymes, against denaturation induced by the external pH
and temperature [108].
1.3.2.7 Nanocomposites
Nanocomposites represent a current trend in developing novel nanostructured bioma-
terials [109]. They comprise a combination of two or more nanostructures containing
different compositions or structures [110,111]. Shen et al. [112] synthesized a multi-
functional nanocomposite of poly(D,L-lactic-co-glycolic acid) (PLGA)-based lumines-
cent/magnetic hybrid nanocomposite modified with polyethyleneimine premodified
with polyethylene glycol-folic acid (PEI-PEG-FA) segments for codelivery of DOX
and VEGF small hairpin RNA (shRNA) (LDM-PLGA/PPF/VEGF shRNA). The
PEG-conjugated copolymer was used to prevent aggregation particles and achieve a
prolonged circulation time, in vivo. PLGA was chosen due to its biocompatibility
and biodegradability. The drug release behavior, folate receptor-mediated cell uptake,
cytotoxicity, escape from endosomes/lysosomes, gene expression, MR and fluores-
cence imaging, and antitumor effects in an animal model of the developed nanocom-
posites were investigated. The nanocomposites revealed a fascinated results and could
be used as a dual-modality imaging nanoprobe for enhanced T2-weighted MR imaging
and tumor fluorescence imaging, both in vitro and in vivo [112]. In a research, Wu
et al. [113] developed DOX-loaded mesoporous magnetic nanocomposites (CS/
Fe3O4@mSiO2-DOX), where chitosan was employed as blocking agent to avoid pre-
mature release of DOX (Fig. 1.4). The release of DOX from these developed DOX-
loaded nanocomposites was revealed for pH responsive behavior and 86.1% DOX
was released at pH 4 within 48 h (Fig. 1.5).
1.3.2.8 Nanoconjugates
Nanotheranostics, particularly nanophototheranostics (which employ photosensi-
tizers), can be considered for treating metastatic and drug-resistant cancers as these
can combine targeting, imaging, and nanoconjugated therapeutic agents [114].
Recently, photosensitizers loaded on nanoscaffolds are widely being used as theranos-
tic nanoconjugates for their capability to serve as both therapeutic and imaging mod-
ules through a single moiety. Near-IR absorbing photosensitizers can take part in
performing both detection and treatment of various diseases. An advantage of using
nanophotosensitizers as theranostic agents is that they tend to possess lower toxicity
and provide sophisticated treatment modules, thus minimizing lengthy recovery
time for patients [115]. Pectin-conjugated graphene oxide nanoconjugate was devel-
oped to deliver anticancer agent-paclitaxel [116]. In vitro cytotoxic studies including
Theranostic nanostructures as nanomedicines: benefits, costs, and future challenges 13](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-26-2048.jpg)
![MTT assay were carried out using L929 and MCF-7 cell lines. Popat et al. [117] syn-
thesized curcumin-cyclodextrin-encapsulated chitosan nanoconjugates with improved
solubility of curcumin and augmented the cellular uptake. Curcumin-cyclodextrin was
synthesized by a novel spray drying method. The scanning electron microscopy (SEM)
indicated the formation of spray dried hollow microspheres (Fig. 1.6).
1.4 Applications of theranostic nanostructures as
nanomedicines
Nanotheranostics has emerged as a fascinated platform for prompt detection and treat-
ment of initially untreatable diseases under conventional therapeutic regimens [118].
Diseases, such as congenital genetic malformations and cancers, can now be easily
diagnosed and treated by employing various imaging techniques adopting genomics,
proteomics, and nanostructures to detect several biomarkers based on understanding
disease pathways [119]. The biomarkers have a great deal of promise as tools for can-
cer detection, diagnosis, patient prognosis, and therapy. Understanding genomics for a
Figure 1.4 Diagram of the preparation and controlled release process of CS/Fe3O4@mSiO2-
DOX [113].
With permission, Copyright © 2016 Elsevier B.V.
14 Design and Applications of Theranostic Nanomedicines](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-27-2048.jpg)
![certain disease is the basis for gene therapy. Recently, a biocompatible poly(D,L-lac-
tide-co-glycolide) (PLG) nanostructures containing an imaging probe and therapeutic
gene were prepared, followed by modification with rabies virus glycoprotein (RVG)
peptide for neuroblastoma-targeting delivery [120]. RVG-modified nanostructures
were effective in specifically targeting neuroblastoma, both in vitro and in vivo.
RVG-modified nanoparticles loaded with a fluorescent probe are helpful to detect
the tumor site in a neuroblastoma-bearing mouse model, and those encapsulating a
therapeutic gene cocktail (siMyc, siBcl-2, and siVEGF) significantly suppressed tumor
growth in the mouse model. This approach for targeted delivery could be useful in
developing multimodality systems for nanotheranostics approaches [120].
Shao et al. [121] fabricated an HSV-TK/GCV suicide gene system and near-
infrared quantum dots for liver cancer treatment tumor imaging. In their study, a
folate-modified theranostic liposome (FL/QD-TK) was developed, composed of an
HSV-TK suicide gene covalently coupling with near-IR fluorescent CdSeTe/ZnS
core/shell quantum dots. The FL/QD-TK exhibited highly specific tumor imaging
and strong inhibition of the folate receptor-overexpressed Bel-7402 mouse xenografts
without systematic toxicity. This study could shed light on gene delivery and targeted
cancer therapy.
Figure 1.5 In vitro cumulative release of DOX from (a) CS/Fe3O4@mSiO2-DOX, (b) CS/
Fe3O4@mSiO2-DOX at 37C in PBS buffer at pH 7.5, 5.8, and 4.0, and (c) First-order model
and (d) Higuchi model of DOX released from CS/Fe3O4@mSiO2-DOX. Results are expressed
as the mean SD of three independent experiments [113].
With permission, Copyright © 2016 Elsevier B.V.
Theranostic nanostructures as nanomedicines: benefits, costs, and future challenges 15](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-28-2048.jpg)
![Surgeons have recently applied advanced nanotheranostics for enhancing surgical
performances and clinical outcomes through medical robotics coupled with miniature
imaging probes. Medical robots have been receiving growing attention due to techno-
logical advances. They have significant potential to reduce the invasiveness and
improve the accessibility of medical devices into unprecedented small spaces inside
the human body. 3D fabrication technologies have enabled medical robotic fabrication
at the single-cell scale for empowering high-resolution visual imaging and in vivo
manipulation capabilities [122]. Injectable ocular nanorobots allow the gastric ulcer
imaging and performance of vitreoretinal microsurgery at previously inaccessible
ocular sites. Many invasive excision and incision based diagnostic and prostrate sur-
gery can be performed minimally or almost noninvasively due to recent advancements
in medical robotics [123]. Such medical robotics systems could be used for local tar-
geted delivery of imaging contrast agents, drugs, genes, and mRNA, minimally inva-
sive surgery, and cell micromanipulation in the near future [122].
1.5 Benefits and costs of theranostic nanostructures as
nanomedicines
Compared with the conventional way of delivering therapeutic or imaging agents sepa-
rately, nanotheranostics encompasses simultaneously delivering imaging and thera-
peutic agents to specific sites or organs. Thus, nanotheranostics enables the
detection and treatment of a disease in a single procedure. When therapeutic and im-
aging agents are formulated in a fixed-dose combination, they are usually assumed to
Figure 1.6 Schematic representations of (a) synthesis of highly soluble curcumin-cyclodextrin
complex by a novel spray drying method. The SEM image represents hollow microspheres
after spray drying and inset shows a water solution of curcumin-cyclodextrin; (b) synthesis
method of curcumin-cyclodextrin-encapsulated chitosan nanoconjugates [117].
16 Design and Applications of Theranostic Nanomedicines](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-29-2048.jpg)
![have similar biodistribution and tumor localization in the body. Consequently, nano-
theranostics agents are expected to inform us about the localization of the drug and
pathological prognosis on a real-time basis.
In situ imaging of theranostic pharmacokinetics can provide important insight into
heterogeneities between tumors and patients. This will benefit physicians for making
informed decisions about timing, dosage adjustments, choice of drug, and treatment
strategies. This constitutes the concept of “personalized medicine,” which can lead
to improved efficacy, lower off-target toxicity, and an overall enhancement of quality
of life and patient treatment outcomes.
1.6 Challenges of theranostic nanostructures as
nanomedicines
Although nanotheranostics is still at its infancy stage in the field of nanomedicine, the
trend toward combining diagnostic and therapeutic functions of theranostic nanostruc-
tures in a single platform has been recently gaining momentum, resulting in signifi-
cantly improved and personalized disease management. However, to realize the
clinical potential of nanotheranostics, researchers should address several challenges.
These challenges may include selecting the ideal nanoplatform, improving ligand
conjugation efficiency, and developing an ideal synthetic technique with fewer
manufacturing steps and high reproducibility. Another issue is the trade-off between
the desired concentration of therapeutic and imaging agents incorporated in the nano-
theranostics platform. That is, how much imaging or therapeutic efficacy is one willing
to sacrifice in order to achieve the desired advantage of having dual functionality. For
instance, while long systemic circulation times are generally preferred for therapeutic
nanostructures, this is not ideal for imaging.
1.7 Conclusion
We have recently witnessed a very fast pace for the growing trend of nanotheranostics
in nanomedicines for disease (especially cancer) imaging and therapy. The current sta-
tus, challenges, and the prospect of tumor actively targeted nanostructures were dis-
cussed in this chapter. The development of nanotheranostics that is targetable, safe,
and efficacious will continue to focus on futuristic applications. The philosophy is
to formulate nanotheranostics that will be holding a greater potential for clinical
applications.
References
[1] Siafaka PI, €
Ust€
unda
g Okur N, Karavas E, Bikiaris DN. Surface modified multifunctional
and stimuli responsive nanoparticles for drug targeting: current status and uses. Int J Mol
Sci 2016;17(9):1440.
Theranostic nanostructures as nanomedicines: benefits, costs, and future challenges 17](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-30-2048.jpg)
![[2] Wande DP, Cui Q, Chen S, Xu C, Xiong H, Yao J. Rediscovering tocophersolan: a re-
naissance for nano-based drug delivery and nanotheranostic applications. Curr Drug
Targets 2021;22(8):856e69.
[3] Qi B, Crawford AJ, Wojtynek NE, Talmon GA, Hollingsworth MA, Ly QP, Mohs AM.
Tuned near infrared fluorescent hyaluronic acid conjugates for delivery to pancreatic
cancer for intraoperative imaging. Theranostics 2020;10(8):3413e29.
[4] Ferber S, Baabur-Cohen H, Blau R, Epshtein Y, Kisin-Finfer E, Redy O, Shabat D,
Satchi-Fainaro R. Polymeric nanotheranostics for real-time non-invasive optical imaging
of breast cancer progression and drug release. Cancer Lett 2014;352(1):81e9.
[5] Das SS, Alkahtani S, Bharadwaj P, Ansari MT, ALKahtani MDF, Pang Z, Hasnain MS,
Nayak AK, Aminabhavi TM. Molecular insights and novel approaches for targeting tu-
mor metastasis. Int J Pharm 2020;585:119556.
[6] Luque-Michel E, Imbuluzqueta E, Sebasti
an V, Blanco-Prieto MJ. Clinical advances of
nanocarrier-based cancer therapy and diagnostics. Expet Opin Drug Deliv 2017;14(1):
75e92.
[7] Pelaz B, Alexiou C, Alvarez-Puebla RA, Alves F, Andrews AM, Ashraf S, Balogh LP,
Ballerini L, Bestetti A, Brendel C, Bosi S, Carril M, Chan WC, Chen C, Chen X, Chen X,
Cheng Z, Cui D, Du J, Dullin C, Escudero A, Feliu N, Gao M, George M, Gogotsi Y,
Gr€
unweller A, Gu Z, Halas NJ, Hampp N, Hartmann RK, Hersam MC, Hunziker P, Jian J,
Jiang X, Jungebluth P, Kadhiresan P, Kataoka K, Khademhosseini A, Kope
cek J,
Kotov NA, Krug HF, Lee DS, Lehr CM, Leong KW, Liang XJ, Ling Lim M, Liz-
Marz
an LM, Ma X, Macchiarini P, Meng H, Möhwald H, Mulvaney P, Nel AE,
Nie S, Nordlander P, Okano T, Oliveira J, Park TH, Penner RM, Prato M, Puntes V,
Rotello VM, Samarakoon A, Schaak RE, Shen Y, Sjöqvist S, Skirtach AG, Soliman MG,
Stevens MM, Sung HW, Tang BZ, Tietze R, Udugama BN, VanEpps JS, Weil T,
Weiss PS, Willner I, Wu Y, Yang L, Yue Z, Zhang Q, Zhang Q, Zhang XE, Zhao Y,
Zhou X, Parak WJ. Diverse applications of nanomedicine. ACS Nano 2017;11(3):
2313e81.
[8] Cole AJ, Yang VC, David AE. Cancer theranostics: the rise of targeted magnetic nano-
particles. Trends Biotechnol 2011;29(7):323e32.
[9] Kelkar SS, Reineke TM. Theranostics: combining imaging and therapy. Bioconjugate
Chem 2011;22(10):1879e903.
[10] Thakkar S, Sharma D, Kalia K, Tekade RK. Tumor microenvironment targeted nano-
therapeutics for cancer therapy and diagnosis: a review. Acta Biomater 2020;101:43e68.
[11] Yang F, Zhao Z, Sun B, Chen Q, Sun J, He Z, Luo C. Nanotherapeutics for antimetastatic
treatment. Trends Cancer 2020;6(8):645e59.
[12] Shao L, Li Q, Zhao C, Lu J, Li X, Chen L, Deng X, Ge G, Wu Y. Auto-fluorescent
polymer nanotheranostics for self-monitoring of cancer therapy via triple-collaborative
strategy. Biomaterials 2019;194:105e16.
[13] Panigrahi BK, Nayak AK. Carbon nanotubes: an emerging drug delivery carrier in cancer
therapeutics. Curr Drug Deliv 2020;17:558e76.
[14] Costa PM, Wang JT, Morfin JF, Khanum T, To W, Sosabowski J, T
oth E, Al-Jamal KT.
Functionalised carbon nanotubes enhance brain delivery of amyloid-targeting pittsburgh
compound B (PiB)-derived ligands. Nanotheranostics 2018;2(2):168e83.
[15] Wang JT, Hodgins NO, Al-Jamal WT, Maher J, Sosabowski JK, Al-Jamal KT. Organ
biodistribution of radiolabelled gd t cells following liposomal alendronate administration
in different mouse tumour models. Nanotheranostics 2020;4(2):71e82.
[16] Bhattacharjee A, Das PJ, Dey S, Nayak AK, Roy PK, Chakrabarti S, Marbaniang D,
Das SK, Ray S, Chattopadhyay P, Mazumder B. Development and optimization of
18 Design and Applications of Theranostic Nanomedicines](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-31-2048.jpg)
![besifloxacin hydrochloride loaded liposomal gel prepared by thin film hydration method
using 32
full factorial design. Colloids Surf A Physicochem Eng Asp 2020;585:124071.
[17] Medalsy I, Dgany O, Sowwan M, Cohen H, Yukashevska A, Wolf SG, Wolf A, Koster A,
Almog O, Marton I, Pouny Y, Altman A, Shoseyov O, Porath D. SP1 protein-based
nanostructures and arrays. Nano Lett 2008;8(2):473e7.
[18] Fu F, Wu Y, Zhu J, Wen S, Shen M, Shi X. Multifunctional lactobionic acid-modified
dendrimers for targeted drug delivery to liver cancer cells: investigating the role played
by PEG spacer. ACS Appl Mater Interfaces 2014;6(18):16416e25.
[19] Jang D, Meza LR, Greer F, Greer JR. Fabrication and deformation of three-dimensional
hollow ceramic nanostructures. Nat Mater 2013;12(10):893e8.
[20] Mardhian DF, Vrynas A, Storm G, Bansal R, Prakash J. FGF2 engineered SPIONs
attenuate tumor stroma and potentiate the effect of chemotherapy in 3D heterospheroidal
model of pancreatic tumor. Nanotheranostics 2020;4(1):26e39.
[21] Sung SY, Su YL, Cheng W, Hu PF, Chiang CS, Chen WT, Hu SH. Graphene quantum
dots-mediated theranostic penetrative delivery of drug and photolytics in deep tumors by
targeted biomimetic nanosponges. Nano Lett 2019;19(1):69e81.
[22] National Research Council. Small wonders, endless frontiers: a review of the national
nanotechnology initiative. Washington, DC: The National Academies Press; 2002.
https://doi.org/10.17226/10395. Retrieved from.
[23] Bayda S, Adeel M, Tuccinardi T, Cordani M, Rizzolio F. The history of nanoscience and
nanotechnology: from chemical-physical applications to nanomedicine. Molecules 2019;
25(1):112.
[24] Mansoori GA, Soelaiman TA. Nanotechnologydan introduction for the standards
community. J ASTM Int (JAI) 2005;2:1e22.
[25] Siafaka PI, Okur N€
U, Karantas ID, Okur ME, G€
undo
gdu EA. Current update on nano-
platforms as therapeutic and diagnostic tools: a review for the materials used as nano-
theranostics and imaging modalities. Asian J Pharm Sci 2021;16(1):24e46.
[26] Hasnain MS, Nayak AK. Carbon nanotubes as quantum dots for therapeutic purpose. In:
Hasnain MS, Nayak AK, editors. Carbon nanotubes for targeted drug delivery.
Singapore: Springer; 2019. p. 59e64.
[27] Jeevanandam J, Barhoum A, Chan YS, Dufresne A, Danquah MK. Review on nano-
particles and nanostructured materials: history, sources, toxicity and regulations. Beilstein
J Nanotechnol 2018;9:1050e74.
[28] Anu Mary Ealia S, Saravanakumar MP. A review on the classification, characterisation,
synthesis of nanoparticles and their application. IOP Conf Ser Mater Sci Eng 2017;263:
032019.
[29] Nasrollahzadeh M, Issaabadi Z, Sajjadi M, Sajadi SM, Atarod M. Chapter 2dtypes of
nanostructures. In: Nasrollahzadeh M, Sajadi SM, Sajjadi M, Issaabadi Z, Atarod T,
editors. An introduction to green nanotechnology. vol 28. USA: Elsevier; 2019.
p. 29e80.
[30] Ansari AA, Hasan TN, Syed NA, Labis JP, Parchur AK, Shafi G, Alshatwi AA. In-vitro
cyto-toxicity, geno-toxicity, and bio-imaging evaluation of one-pot synthesized lumi-
nescent functionalized mesoporous SiO2@Eu(OH)3 core-shell microspheres. Nano-
medicine 2013;9(8):1328e35.
[31] Hasnain MS, Nayak AK. Background: carbon Nanotubes for targeted drug delivery. In:
Hasnain MS, Nayak AK, editors. Carbon nanotubes for targeted drug delivery.
Singapore: Springer; 2019. p. 1e9.
[32] Hasnain MS, Nayak AK. Classification of carbon nanotubes. In: Hasnain MS, Nayak AK,
editors. Carbon nanotubes for targeted drug delivery. Singapore: Springer; 2019. p. 11e5.
Theranostic nanostructures as nanomedicines: benefits, costs, and future challenges 19](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-32-2048.jpg)
![[33] Kostarelos K, Bianco A, Prato M. Promises, facts and challenges for carbon nanotubes in
imaging and therapeutics. Nat Nanotechnol 2009;4(10):627e33.
[34] Hasnain MS, Nayak AK. Characterization of carbon nanotubes. In: Hasnain MS,
Nayak AK, editors. Carbon nanotubes for targeted drug delivery. Singapore: Springer;
2019. p. 29e31.
[35] Kang B, Yu D, Dai Y, Chang S, Chen D, Ding Y. Cancer-cell targeting and photoacoustic
therapy using carbon nanotubes as “bomb” agents. Small 2009;5(11):1292e301.
[36] Zavaleta C, de la Zerda A, Liu Z, Keren S, Cheng Z, Schipper M, Chen X, Dai H,
Gambhir SS. Noninvasive Raman spectroscopy in living mice for evaluation of tumor
targeting with carbon nanotubes. Nano Lett 2008;8(9):2800e5.
[37] Hasnain MS, Nayak AK. Carbon nanotubes in controlled drug delivery. In: Hasnain MS,
Nayak AK, editors. Carbon nanotubes for targeted drug delivery. Singapore: Springer;
2019. p. 51e4.
[38] Hasnain MS, Nayak AK. Toxicity consideration of carbon nanotubes. In: Hasnain MS,
Nayak AK, editors. Carbon nanotubes for targeted drug delivery. Singapore: Springer;
2019. p. 89e101.
[39] Schipper ML, Nakayama-Ratchford N, Davis CR, Kam NW, Chu P, Liu Z, Sun X, Dai H,
Gambhir SS. A pilot toxicology study of single-walled carbon nanotubes in a small
sample of mice. Nat Nanotechnol 2008;3(4):216e21.
[40] Kumar V, Kumar A, Lee DJ, Park SS. Estimation of number of graphene layers using
different methods: a focused review. Materials 2021;14(16):4590.
[41] Bhuyan MSA, Uddin MN, Islam MM, et al. Synthesis of graphene. Int Nano Lett 2016;6:
65e83.
[42] Kumar M, Raza K. C60-fullerenes as drug delivery carriers for anticancer agents:
promises and hurdles. Pharm Nanotechnol 2017;5(3):169e79.
[43] Thakral S, Mehta RM. Fullerenes: an introduction and overview of their biological
properties. Indian J Pharmaceut Sci 2006;68:13e9.
[44] Patra JK, Das G, Fraceto LF, Campos EVR, Rodriguez-Torres MDP, Acosta-Torres LS,
Diaz-Torres LA, Grillo R, Swamy MK, Sharma S, Habtemariam S, Shin HS. Nano based
drug delivery systems: recent developments and future prospects. J Nanobiotechnol 2018;
16(1):71.
[45] Hussein Kamareddine M, Ghosn Y, Tawk A, Elia C, Alam W, Makdessi J, Farhat S.
Organic nanoparticles as drug delivery systems and their potential role in the treatment of
chronic myeloid leukemia. Technol Cancer Res Treat 2019;18. 1533033819879902.
[46] Abbasi E, Aval SF, Akbarzadeh A, Milani M, Nasrabadi HT, Joo SW, Hanifehpour Y,
Nejati-Koshki K, Pashaei-Asl R. Dendrimers: synthesis, applications, and properties.
Nanoscale Res Lett 2014;9(1):247.
[47] Ghosh B, Biswas S. Polymeric micelles in cancer therapy: state of the art. J Contr Release
2021;332:127e47.
[48] Ghezzi M, Pescina S, Padula C, Santi P, Del Favero E, Cant
u L, Nicoli S. Polymeric
micelles in drug delivery: an insight of the techniques for their characterization and
assessment in biorelevant conditions. J Contr Release 2021;332:312e36.
[49] Khafaji M, Zamani M, Golizadeh M, Bavi O. Inorganic nanomaterials for chemo/pho-
tothermal therapy: a promising horizon on effective cancer treatment. Biophys Rev 2019;
11(3):335e52.
[50] Fan Z, Huang X, Tan C, Zhang H. Thin metal nanostructures: synthesis, properties and
applications. Chem Sci 2015;6(1):95e111.
[51] Huo D, Kim MJ, Lyu Z, Shi Y, Wiley BJ, Xia Y. One-dimensional metal nanostructures:
from colloidal syntheses to applications. Chem Rev 2019;119(15):8972e9073.
20 Design and Applications of Theranostic Nanomedicines](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-33-2048.jpg)
![[52] Ye J, Helmi S, Teske J, Seidel R. Fabrication of metal nanostructures with programmable
length and patterns using a modular DNA platform. Nano Lett 2019;19(4):2707e14.
[53] Yi Z, Yi Y, Luo J, Ye X, Wu P, Ji X, Jiang X, Yi Y, Tang Y. Experimental and simulative
study on surface enhanced Raman scattering of rhodamine 6G adsorbed on big bulk-
nanocrystalline metal substrates. RSC Adv 2015;5:1718e29.
[54] Fan Z, Lu JG. Zinc oxide nanostructures: synthesis and properties. J Nanosci Nano-
technol 2005;5(10):1561e73.
[55] Hu SB, Li L, Luo MY, Yun YF, Chang CT. Aqueous norfloxacin sonocatalytic degra-
dation with multilayer flower-like ZnO in the presence of peroxydisulfate. Ultrason
Sonochem September 2017;38:446e54.
[56] Wang ZL. Zinc oxide nanostructures: growth, properties and applications. J Phys Con-
dens Matter 2004;16:829e58.
[57] Laurent S, Forge D, Port M, Roch A, Robic C, Vander Elst L, Muller RN. Magnetic iron
oxide nanoparticles: synthesis, stabilization, vectorization, physicochemical character-
izations, and biological applications. Chem Rev 2008;108(6):2064e110.
[58] Yu MK, Jeong YY, Park J, Park S, Kim JW, Min JJ, Kim K, Jon S. Drug-loaded
superparamagnetic iron oxide nanoparticles for combined cancer imaging and therapy
in vivo. Angew Chem Int Ed Engl 2008;47(29):5362e5.
[59] Dilnawaz F, Singh A, Mohanty C, Sahoo SK. Dual drug loaded superparamagnetic iron
oxide nanoparticles for targeted cancer therapy. Biomaterials 2010;31(13):3694e706.
[60] Jun YW, Lee JH, Cheon J. Chemical design of nanoparticle probes for high-performance
magnetic resonance imaging. Angew Chem Int Ed Engl 2008;47(28):5122e35.
[61] Chen F, Ehlerding EB, Cai W. Theranostic nanoparticles. J Nucl Med 2014;55(12):
1919e22.
[62] Labhasetwar V, Zborowski M, Abramson AR, Basilion JP. Nanoparticles for imaging,
diagnosis, and therapeutics. Mol Pharm 2009;6(5):1261e2.
[63] Lee DE, Koo H, Sun IC, Ryu JH, Kim K, Kwon IC. Multifunctional nanoparticles for
multimodal imaging and theragnosis. Chem Soc Rev 2012;41(7):2656e72.
[64] Minelli C, Lowe SB, Stevens MM. Engineering nanocomposite materials for cancer
therapy. Small 2010;6(21):2336e57.
[65] Muthu MS, Leong DT, Mei L, Feng SS. Nanotheranosticsdapplication and further
development of nanomedicine strategies for advanced theranostics. Theranostics 2014;
4(6):660e77.
[66] Ferrari M. Cancer nanotechnology: opportunities and challenges. Nat Rev Cancer 2005;
5(3):161e71.
[67] Depalo N, Iacobazzi RM, Valente G, Arduino I, Villa S, Canepa F, Laquintana V,
Fanizza E, Striccoli M, Cutrignelli A, Lopedota A, Porcelli L, Azzariti A, Franco M,
Curri ML, Denora N. Sorafenib delivery nanoplatform based on superparamagnetic iron
oxide nanoparticles magnetically targets hepatocellular carcinoma. Nano Res 2017;10:
2431e48.
[68] Cheung-Ong K, Giaever G, Nislow C. DNA-damaging agents in cancer chemotherapy:
serendipity and chemical biology. Chem Biol 2013;20(5):648e59.
[69] Zhang NN, Yu RS, Xu M, Cheng XY, Chen CM, Xu XL, Lu CY, Lu KJ, Chen MJ,
Zhu ML, Weng QY, Hui JG, Zhang Q, Du YZ, Ji JS. Visual targeted therapy of hepatic
cancer using homing peptide modified calcium phosphate nanoparticles loading doxo-
rubicin guided by T1 weighted MRI. Nanomedicine 2018;14(7):2167e78.
[70] Mishra N, Yadav NP, Rai VK, Sinha P, Yadav KS, Jain S, Arora S. Efficient hepatic
delivery of drugs: novel strategies and their significance. BioMed Res Int 2013;2013:
382184.
Theranostic nanostructures as nanomedicines: benefits, costs, and future challenges 21](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-34-2048.jpg)
![[71] Lata S, Sharma G, Joshi M, Kanwar P, Mishra T. Role of nanotechnology in drug de-
livery. Int J Nanotechnol Nanosci 2017;7(5):1e29.
[72] Amreddy N, Babu A, Muralidharan R, Panneerselvam J, Srivastava A, Ahmed R,
Mehta M, Munshi A, Ramesh R. Recent advances in nanoparticle-based cancer drug and
gene delivery. Adv Cancer Res 2018;137:115e70.
[73] Ashfaq UA, Riaz M, Yasmeen E, Yousaf MZ. Recent advances in nanoparticle-based
targeted drug-delivery systems against cancer and role of tumor microenvironment.
Crit Rev Ther Drug Carrier Syst 2017;34(4):317e53.
[74] Ng TSC, Garlin MA, Weissleder R, Miller MA. Improving nanotherapy delivery and
action through image-guided systems pharmacology. Theranostics 2020;10(3):968e97.
[75] Lim EK, Kim T, Paik S, Haam S, Huh YM, Lee K. Nanomaterials for theranostics: recent
advances and future challenges. Chem Rev 2015;115(1):327e94.
[76] Qian HS, Guo HC, Ho PC, Mahendran R, Zhang Y. Mesoporous-silica-coated up-
conversion fluorescent nanoparticles for photodynamic therapy. Small 2009;5(20):
2285e90.
[77] Wu SH, Lin YS, Hung Y, Chou YH, Hsu YH, Chang C, Mou CY. Multifunctional
mesoporous silica nanoparticles for intracellular labeling and animal magnetic resonance
imaging studies. Chembiochem January 4, 2008;9(1):53e7.
[78] Talanov VS, Regino CA, Kobayashi H, Bernardo M, Choyke PL, Brechbiel MW.
Dendrimer-based nanoprobe for dual modality magnetic resonance and fluorescence
imaging. Nano Lett 2006;6(7):1459e63.
[79] Kessenbrock K, Plaks V, Werb Z. Matrix metalloproteinases: regulators of the tumor
microenvironment. Cell 2010;141(1):52e67.
[80] Cathcart J, Pulkoski-Gross A, Cao J. Targeting matrix metalloproteinases in cancer:
bringing new life to old ideas. Genes Dis 2015;2(`1):26e34.
[81] Bieliuniene E, Frøkjær JB, Pockevicius A, Kemesiene J, Lukosevicius S, Basevicius A,
Barauskas G, Dambrauskas Z, Gulbinas A. Magnetic resonance imaging as a valid
noninvasive tool for the assessment of pancreatic fibrosis. Pancreas 2019;48(1):85e93.
[82] Su Y, Deng L, Yang L, Yuan X, Xia W, Liu P. Magnetic resonance imaging for the non-
invasive diagnosis in patients with ovarian cancer: a protocol for systematic review and
meta-analysis. Medicine (Baltim) 2020;99(50):e23551.
[83] Ding H, Wu F. Image guided biodistribution and pharmacokinetic studies of theranostics.
Theranostics 2012;2(11):1040e53.
[84] Mulder WJ, Strijkers GJ, Griffioen AW, van Bloois L, Molema G, Storm G, Koning GA,
Nicolay K. A liposomal system for contrast-enhanced magnetic resonance imaging of
molecular targets. Bioconjugate Chem 2004;15(4):799e806.
[85] Kim D, Jeong YY, Jon S. A drug-loaded aptamer-gold nanoparticle bioconjugate for
combined CT imaging and therapy of prostate cancer. ACS Nano 2010;4(7):3689e96.
[86] Zhu J, Zheng L, Wen S, Tang Y, Shen M, Zhang G, Shi X. Targeted cancer theranostics
using alpha-tocopheryl succinate-conjugated multifunctional dendrimer-entrapped gold
nanoparticles. Biomaterials 2014;35(26):7635e46.
[87] Vasudev NS, Reynolds AR. Anti-angiogenic therapy for cancer: current progress, un-
resolved questions and future directions. Angiogenesis 2014;17(3):471e94.
[88] Mendes LP, Lima EM, Torchilin VP. Drug delivery in cancer. In: Handbook of nano-
materials for cancer theranostics. Elsevier Inc; 2018. https://doi.org/10.1016/B978-0-12-
813339-2.00009-8.
[89] Han N, Yang YY, Wang S, Zheng S, Fan W. Polymer-based cancer nanotheranostics:
retrospectives of multi-functionalities and pharmacokinetics. Curr Drug Metabol 2013;
14(6):661e74.
22 Design and Applications of Theranostic Nanomedicines](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-35-2048.jpg)
![[90] Sachdev A, Matai I, Gopinath P. Carbon dots incorporated polymeric hydrogels as
multifunctional platform for imaging and induction of apoptosis in lung cancer cells.
Colloids Surf B Biointerfaces 2016;141:242e52.
[91] Xing H, Hwang K, Lu Y. Recent developments of liposomes as nanocarriers for thera-
nostic applications. Theranostics 2016;6(9):1336e52.
[92] Muthu MS, Feng SS. Theranostic liposomes for cancer diagnosis and treatment: current
development and pre-clinical success. Expet Opin Drug Deliv 2013;10(2):151e5.
[93] Soares DCF, De Sousa GF, De Barros ALB, Cardoso VN, De Oliveira MC,
Ramaldes GA. Scintigraphic imaging and increment in mice survival using theranostic
liposomes based on Gadolinium-159. J Drug Deliv Sci Technol 2015;30:7e14.
[94] Al-Jamal WT, Kostarelos K. Liposomes: from a clinically established drug delivery
system to a nanoparticle platform for theranostic nanomedicine. Acc Chem Res 2011;
44(10):1094e104.
[95] Fahmy TM, Fong PM, Park J, Constable T, Saltzman WM. Nanosystems for simulta-
neous imaging and drug delivery to T cells. AAPS J 2007;9(2):E171e80.
[96] Bosman AW, Janssen HM, Meijer EW. About dendrimers: structure, physical properties,
and applications. Chem Rev 1999;99(7):1665e88.
[97] Jansen JF, de Brabander-van den Berg EM, Meijer EW. Encapsulation of guest molecules
into a dendritic box. Science 1994;266(5188):1226e9.
[98] Liu X, Wang C, Liu Z. Protein-engineered biomaterials for cancer theranostics. Adv
Healthc Mater October 2018;7(20):e1800913.
[99] Silva CO, Pinho JO, Lopes JM, Almeida AJ, Gaspar MM, Reis C. Current trends in
cancer nanotheranostics: metallic, polymeric, and lipid-based systems. Pharmaceutics
2019;11(1):22.
[100] Zhang Q, Yang M, Zhu Y, Mao C. Metallic nanoclusters for cancer imaging and therapy.
Curr Med Chem 2018;25(12):1379e96.
[101] Link S, El-Sayed MA. Shape and size dependence of radiative, non-radiative and pho-
tothermal properties of gold nanocrystals. Int Rev Phys Chem 2000;19(3):409e53.
[102] Kumar R, Korideck H, Ngwa W, Berbeco RI, Makrigiorgos GM, Sridhar S. Third
generation gold nanoplatform optimized for radiation therapy. Transl Cancer Res 2013;
2(4). https://doi.org/10.3978/j.issn.2218-676X.2013.07.02.
[103] Han G, Martin CT, Rotello VM. Stability of gold nanoparticle-bound DNA toward
biological, physical, and chemical agents. Chem Biol Drug Des 2006;67(1):78e82.
[104] Nandwana V, De M, Chu S, Jaiswal M, Rotz M, Meade TJ, Dravid VP. Theranostic
magnetic nanostructures (MNS) for cancer. Cancer Treat Res 2015;166:51e83.
[105] Zhu L, Zhou Z, Mao H, Yang L. Magnetic nanoparticles for precision oncology: thera-
nostic magnetic iron oxide nanoparticles for image-guided and targeted cancer therapy.
Nanomedicine January 2017;12(1):73e87.
[106] Bobo D, Robinson KJ, Islam J, Thurecht KJ, Corrie SR. Nanoparticle-based medicines: a
review of FDA-approved materials and clinical trials to date. Pharm Res (N Y) 2016;
33(10):2373e87.
[107] Liu J, Liu T, Pan J, Liu S, Lu GQM. Advances in multicompartment mesoporous silica
micro/nanoparticles for theranostic applications. Annu Rev Chem Biomol Eng 2018;9:
389e411.
[108] Mishra D, Hubenak JR, Mathur AB. Nanoparticle systems as tools to improve drug
delivery and therapeutic efficacy. J Biomed Mater Res December 2013;101(12):
3646e60.
Theranostic nanostructures as nanomedicines: benefits, costs, and future challenges 23](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-36-2048.jpg)
![[109] Nayak AK, Alkahtani S, Hasnain MS. Biomedical nanocomposites. In: Nayak AK,
Hasnain MH, editors. Biomedical composites-perspectives and applications. Switzerland
AG: Springer International Publishing, Springer Nature; 2021. p. 35e69.
[110] Hasnain MS, Nayak AK. Nanocomposites for improved orthopedic and bone tissue en-
gineering applications. In: Inamuddin, Asiri AM, Mohammad A, editors. Applications of
nanocomposite Materials in orthopedics, woodhead publishing series in biomaterials.
United States: Elsevier Inc.; 2019. p. 145e77.
[111] Hasnain MS, Ahmad SA, Chaudhary N, Hoda MN, Nayak AK. Biodegradable polymer
matrix nanocomposites for bone tissue engineering. In: Inamuddin, Asiri AM,
Mohammad A, editors. Applications of nanocomposite Materials in orthopedics, wood-
head publishing series in biomaterials. United States: Elsevier Inc.; 2019. p. 1e37.
[112] Shen X, Li T, Chen Z, Geng Y, Xie X, Li S, Yang H, Wu C, Liu Y. Luminescent/
magnetic PLGA-based hybrid nanocomposites: a smart nanocarrier system for targeted
codelivery and dual-modality imaging in cancer theranostics. Int J Nanomed 2017;12:
4299e322.
[113] Wu J, Jiang W, Shen Y, Jiang W, Tian R. Synthesis and characterization of mesoporous
magnetic nanocomposites wrapped with chitosan gatekeepers for pH-sensitive controlled
release of doxorubicin. Mater Sci Eng C Mater Biol Appl 2017;70(Pt 1):132e40.
[114] Kievit FM, Zhang M. Cancer nanotheranostics: improving imaging and therapy by tar-
geted delivery across biological barriers. Adv Mater 2011;23(36):H217e47.
[115] Bhaumik J, Mittal A, Banerjee A, Chisti Y, Banerjee UC. Applications of photo-
theranostic nanoagents in photodynamic therapy. Nano Res 2014;8:1373e94.
[116] Hussien NA, Isıklan N, Turk M. Pectin-conjugated magnetic graphene oxide nanohybrid
as a novel drug carrier for paclitaxel delivery. Artif Cell Nanomed Biotechnol 2018:
1e10.
[117] Popat A, Karmakar S, Jambhrunkar S, Xu C, Yu C. Curcumin-cyclodextrin encapsulated
chitosan nanoconjugates with enhanced solubility and cell cytotoxicity. Colloids Surf B
Biointerfaces 2004;117:520e7.
[118] Roma-Rodrigues C, Pombo I, Raposo L, Pedrosa P, Fernandes AR, Baptista PV.
Nanotheranostics targeting the tumor microenvironment. Front Bioeng Biotechnol 2019;
7:197.
[119] Yao J, Yang M, Duan Y. Chemistry, biology, and medicine of fluorescent nanomaterials
and related systems: new insights into biosensing, bioimaging, genomics, diagnostics,
and therapy. Chem Rev 2014;114(12):6130e78.
[120] Lee J, Jeong EJ, Lee YK, Kim K, Kwon IC, Lee KY. Optical imaging and gene therapy
with neuroblastoma-targeting polymeric nanoparticles for potential theranostic applica-
tions. Small 2016;12(9):1201e11.
[121] Shao D, Li J, Pan Y, Zhang X, Zheng X, Wang Z, Zhang M, Zhang H, Chen L.
Noninvasive theranostic imaging of HSV-TK/GCV suicide gene therapy in liver cancer
by folate-targeted quantum dot-based liposomes. Biomater Sci 2015;3(6):833e41.
[122] Singh AV, Sitti M. Targeted drug delivery and imaging using mobile milli/microrobots: a
promising future towards theranostic pharmaceutical design. Curr Pharmaceut Des 2016;
22(11):1418e28.
[123] L€
utje S, Rijpkema M, Franssen GM, Fracasso G, Helfrich W, Eek A, Oyen WJ,
Colombatti M, Boerman OC. Dual-modality image-guided surgery of prostate cancer
with a radiolabeled fluorescent anti-PSMA monoclonal antibody. J Nucl Med 2014;55(6):
995e1001.
24 Design and Applications of Theranostic Nanomedicines](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-37-2048.jpg)
![Theranostic nanogels: design and
applications 2
Mayra A. Mendez-Encinas 1
and Elizabeth Carvajal-Millan 2
1
Department of Chemical Biological and Agropecuary Sciences, University of Sonora,
Avenida Universidad e Irigoyen, Caborca, Sonora, Mexico; 2
Biopolymers, Research Center
for Food and Development, CIAD A.C., Carretera Gustavo E. Astiazaran Rosas No. 46,
Hermosillo, Sonora, Mexico
2.1 Introduction
Theranostics comprise those novel strategies combining disease diagnosis and therapy
for a broad range of applications in the field of medicine. Nanotechnology has offered
an opportunity to develop systems that combine diagnosis and therapy for theranostic
purposes. Nanoformulations are considered excellent systems for use in theranostic ap-
plications because they can improve the biodistribution and the target site accumula-
tion of the administered therapeutic agent [1]. Nanotheranostics refers to the
application of nanomedicine strategies for the development of novel
nanoformulations-based systems that combine disease diagnosis and targeted-
delivery of therapeutics simultaneously in a single platform. The main objective of
these theranostic systems is to treat and diagnose the disease at an early stage [2].
Theranostic nanoformulations consist of colloidal nanoparticles (NPs) ranging in sizes
from 10 to 1000 nm made from macromolecular materials/polymers in which the diag-
nostic and therapeutic agent are encapsulated, entrapped, conjugated, or adsorbed for
diagnosis and treatment simultaneously at cellular and molecular level [2]. The thera-
peutic agents include hydrophobic organic drugs, proteins, peptides, and genetic ma-
terial, while the diagnostic agents are those used for optical imaging, magnetic
resonance imaging, nuclear imaging, ultrasound imaging, among others [2]. Several
NPs have been explored as platforms for theranostic purposes including metallic
NPs, mesoporous silica particles, carbon-based NPs, and polymeric nanogels [3].
Among these, nanogels have demonstrated to be an attractive choice for theranostic
applications. This chapter focuses on describing different designs of theranostic nano-
gels based on the principal methods used for imaging. Moreover, the application of
these theranostic nanogels is discussed.
2.2 Nanogels
Nanogels (NGs) are hydrogels or particles with a submicron size ranging from 20 to
200 nm composed of three-dimensional cross-linked polymers networks that exhibit
Design and Applications of Theranostic Nanomedicines. https://doi.org/10.1016/B978-0-323-89953-6.00003-9
Copyright © 2023 Elsevier Ltd. All rights reserved.](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-38-2048.jpg)
![high water absorption capacity [4]. These materials have gained increased attention in
the biomedical field due to their attractive properties. The properties of NGs include
biocompatibility and biodegradability, easy and higher drug loading capacity, stability
of entrapped drug, physical stability, swelling capacity in aqueous media, versatility in
design and easy formulation, and others [5,6]. Besides, NGs exhibit stimuli-responsive
nature, permeability, and small particle size, as well as the ability to control the release
of a wide variety of bioactive molecules making them materials with suitable charac-
teristics for drug delivery systems [5,6]. Fig. 2.1 shows the most relevant attributes of
NGs for their application as drug delivery systems.
NGs can be prepared through different methods such as in situ polymerization and
cross-linking of hydrophilic monomers, or via cross-linking of hydrophilic copolymers
containing functional groups using cross-linkers [7,8]. The bioactive molecules, which
are usually drugs, can be loaded into the NG via physical or chemical interactions
between the molecule and the functional groups in the polymer network [6]. Moreover,
the incorporation of ligands into the gel structure allows a high selectivity and a
target-site drug delivery, preventing the accumulation of drug in unspecific sites [9].
According to the method of preparation and type of linkages formed in the cross-
linked polymeric network, NGs can be classified as physically cross-linked NGs
and chemically cross-linked NGs. Physically cross-linked NGs involve non-covalent
type interactions (hydrogen bonds, electrostatic interactions, van der Waals forces,
etc.) between the polymer chains forming the three-dimensional polymer network
Figure 2.1 Attributes of NGs for their application as drug delivery systems.
28 Design and Applications of Theranostic Nanomedicines](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-39-2048.jpg)
![[6,9]. On the opposite, chemically cross-linked NGs are formed by covalent cross-
linked polymer networks, where a cross-linking agent (chemical or enzymatic) is
needed to join the polymer chains [9]. Due to their covalent nature consisting of disul-
fide or amine based bonds, and sometimes via enzymatic or photo-induced cross-
linking, chemical NGs are stronger and more stable than physical gels [6].
Due to their versatility, NGs are suitable for numerous applications in the biomed-
ical field, including tissue engineering, wound healing, drug delivery, bioimaging,
among others. However, one of their most promising applications is as drug delivery
systems due to their physicochemical and biological properties that allow them to
achieve a site-specific delivery of the entrapped drug [10]. In addition, they can be
administered through different routes including oral, pulmonary, nasal, intraocular,
nasal, and parenteral [9]. Thus, NGs as drug delivery systems can be exploited for
different purposes including the treatment of different diseases, gene therapy, inflam-
matory disorders, tissue engineering, and others (Fig. 2.2) [4].
2.3 Theranostic nanogels
Recently, NGs have been extensively explored for theranostic applications. NGs pro-
vide extraordinary advantages for application as theranostic platforms in comparison
to other systems such as micelles, liposomes, and others [11]. Some of these features
Figure 2.2 Biomedical applications of NGs.
Adapted from Sabir F, Asad MI, Qindeel M, Afzal I, Dar MJ, Shah KU, et al. Polymeric
nanogels as versatile nanoplatforms for biomedical applications. J Nanomater 2019.
Theranostic nanogels: design and applications 29](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-40-2048.jpg)
![are their high biocompatibility and biodegradability, high drug loading capacity, con-
trol release ability, swelling capacity, among others [12]. Besides their high stability
and facile dispersibility, NGs allow the incorporation of both diagnostics (imaging
agents) and therapeutic agents (drugs, biomolecules) in a single platform [13]. The
modification of the NG structure through the incorporation of functional groups allows
the development of NGs with stimuli-response capacity that can react to different stim-
ulus such as pH, temperature, light, magnetic field, and redox environment [14]. Thus,
stimuli-responsive NGs respond to either endogenous or exogenous stimulus
providing an effective biodistribution and controlled release of bioactive agents at
target sites [15], being therefore an excellent tool for theranostic purposes.
Theranostic NGs are systems consisting of an imaging component, a therapeutic
agent and a targeting ligand [3]. The therapeutic agents which are usually drugs, genes,
or photosensitizers can be incorporated into the NG by physical entrapment or chem-
ical conjugation methods [16]. The diagnostic agents and the targeting ligands are con-
jugated in the surface of the NG structure [17]. The imaging function of NG systems
can be accomplished by its loading or conjugation with imaging agents such as dots,
organic dyes, radiolabels, and magnetic particles [3]. In this sense, different imaging
techniques have been explored for diagnostics in theranostics applications, including
optical imaging, magnetic resonance imaging (MRI), ultrasound imaging (USI), pho-
toacoustic imaging (PAI), nuclear imaging, single photon emission computed tomog-
raphy (SPECT), and others [15]. Typically, external imaging agents (quantum dots,
organic dyes, radiolabels, and MRI contrast agents) are loaded into the gel along
with the therapeutic agent during the NG preparation in order to create a simultaneous
diagnosis and therapeutic system [3]. Because sometimes a premature leakage of the
image agent before the NG reaches the target site can occur resulting in an unspecific
biodistribution of the drug and a potential toxicity [14], novel NGs with innate imaging
potential have also been designed in order to avoid these drawbacks [3]. Theranostic
NGs have been mainly studied for application in cancer diagnosis and imaging-guided
cancer therapy [6,11]. In the field of cancer treatment, the use of powerful diagnostic
methods that permit a real-time monitoring of the therapeutic process may provide a
precise and personalized treatment [11]. Therefore, the interest in the development
of imaging-guided cancer therapeutic systems has increased in the last years.
2.4 Designs of theranostic nanogels
Nowadays, the increasing progress in material sciences have provided all tools
required for the designing of a wide variety of theranostic systems. The designs of a
theranostic NG will mainly depend on the desired purposes and the method used for
its preparation.
Depending on the nature of the materials constituting the system, NGs can be clas-
sified based in organic and organic/inorganic (hybrid) NGs (Fig. 2.3). Organic NGs are
considered those prepared by cross-linking functional macromolecules which were
previously synthesized through the modification of their functional groups. The other
30 Design and Applications of Theranostic Nanomedicines](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-41-2048.jpg)
![type of NGs consist in inorganic NPs coated with cross-linked organic shells. Due to
their nature, inorganic NPs are poor biocompatible and highly unstable under physio-
logical conditions, being therefore necessary coating their surfaces with biocompatible
materials. Thus, the entrapment of these inorganic particles into NGs to form core-shell
structures help to enhance considerably their stability and biocompatibility [11].
The diagnostic function of the theranostic NG will also have an important influence
on the theranostic platforms’ design as it determines the most appropriate diagnostic
agent for the desired purposes. Besides, once the diagnostic agent has been selected,
it is necessary to establish the adequate imaging tools to assure an optimum diagnostic
function. Several imaging modalities have been incorporated into NGs to accomplish
the diagnostic function, including optical imaging, MRI, PAI, USI, and others. More-
over, the development of multimodal nanoplatforms incorporating two or more imag-
ing modes have gained attention. Bioimaging is a novel noninvasive technique used to
observe the biological behavior over a given period of time without disturbing the life
cycles (movement and respiration, etc.) with the objective of recording the specimen’s
3D structure with minimal inconvenience. This method is very useful in linking sub-
cellular structure observations and all tissues in multicellular organism [18]; therefore,
it has been widely used in several clinical applications. In the next section, the char-
acteristics and applications of theranostic NGs are described based on the imaging
technique used for the diagnostic purposes.
Figure 2.3 Schematic illustration for preparation of cross-linked NGs. (a) Preparation of
macromolecules-based cross-linked NGs. (b) Preparation of inorganic NPs-based cross-linked
NGs.
Adapted from Zhou W, Yang G, Ni X, Diao S, Xie C, Fan Q. Recent advances in crosslinked
nanogel for multimodal imaging and cancer therapy. Polymers 2020;12(9).
Theranostic nanogels: design and applications 31](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-42-2048.jpg)
![2.4.1 Optical imaging
For theranostic purposes, optical imaging is among the most commonly used tech-
niques for bioimaging due to their multiple advantages including high safety and sensi-
tivity, low cost and capability of multichannel imaging [11,19]. These systems, called
phototheranostics, based on optical imaging have demonstrated promising expectative
for application mainly in cancer imaging and therapy [11]. Optical fluorescence can be
categorized according to the emission wavelength in near-infrared (NIR,
750e1000 nm), visible light (450e750 nm), and ultraviolet (320e450 nm) [19].
Several imaging agents including fluorescent dyes, quantum dots, and metallic NPs
can be incorporated into the NG system for detection by optical imaging. In addition,
the development of novel NGs with innate fluorescence have been explored. NGs
incorporating this imaging modality have been widely studied using in vitro as well
as in vivo models in order to prove their potential application in imaging-guided cancer
treatment. Table 2.1 shows some theranostic NGs designed for diagnostic based on op-
tical imaging techniques.
Recently, the theranostic research field has increased its interest in NGs systems
where the use of external imaging agents is not necessary. There are some concerns
related to the stability of the bonds formed during the conjugation of imaging agents
into the NG surface. The exposure of these systems to certain physiological conditions
such as enzymes or pH changes could lead to the break of the bonds and subsequent
loss of the imaging agent before reaching the target site [3]. Organic dyes and quantum
dots are among the fluorescence probes most widely used that can be encapsulated
within or conjugated to the NP system. However, some of their disadvantages are
that organic dyes exert poor photochemical stability and exert rapid photo bleaching,
while the metals cadmium and selenide contained in quantum dots are toxic to organ-
isms [20]. For these reasons, the exploration of new materials with intrinsic or innate
fluorescence has greatly increase in the last years. Gyawally et al. [20] developed a
highly photostable NG for fluorescence-based theranostics. The NG was prepared us-
ing biocompatible monomers (citric acid, maleic acid, L-cysteine, and PEG) and its
surface functionalized with RGD (Arg, Gly, Asp) peptides and encapsulated with an
anticancer drug (DOX). The system exhibited pH-responsive controlled drug release
in acidic pH tumor environment and strong fluorescence allowing tracking of targeted
drug delivery in cytoplasmic regions of prostate cancer cells to induce cell death. The
system demonstrated to be a strong candidate for theranostic medicine due to its high
stability and capacity for real-time fluorescence-based monitoring drug delivery. In a
similar way, Vijayan et al. [17] designed a novel theranostic probe by conjugating
octreotide (natural growth hormone) with an NIR-emitting NG (PMB-OctN). The fluo-
rescent NG, synthetized based on photoluminiscent cromacromer (PEG-maleic acid-4
aminobenzoic), diethylene glycoldimethacrylate, and octreotide was loaded with DOX
in order to construct the theranostic probe. The PMB-OctN demonstrated NIR imaging
capability and increased cellular uptake in cervical cancer cells. Moreover, in vivo
studies using mice revealed longer in vivo circulation lifetime. The results suggested
this system as a promising candidate for theranostic purposes.
32 Design and Applications of Theranostic Nanomedicines](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-43-2048.jpg)
![Table 2.1 Theranostic NGs platforms using optical imaging modality for diagnostic function.
Theranostic
NG design Imaging agent
Therapeutic
agent/method
In vitro/
in vivo
model References
Clickable NGs
via thermally
driven self-
assembly of
polymers
Thiol-bearing
hydrophobic
dye (BODIPY-
SH) and N-
(fluoresceinyl)
maleimide
Cyclic-peptide-base
targeting group
(cRGDfC)
MDA-MB-
231 breast
cancer
cells
[8]
Highly
photostable
NG for
fluorescence-
based
theranostics
Innate
fluorescence
DOX Prostate
cancer
cells
[20]
Alginate-based
cancer-
associated,
stimuli-driven
and turn-on
theranostic
prodrug NGs
Rhodamine B DOX HepG2 cells [21]
Theranostic
alginate-
based
cisplatin-
loaded NGs
Fluorophore
ATTO655
Cisplatin Macrophage
cell line
J7744.1
[22]
HDMVECn
(normal
cell line)
Multifunctional
NG with
reversible and
nonreversible
linkages
Cy5 dye DOX MDA-MB-
231 breast
cancer
cells
[13]
Magneto-
fluorescent
hybrid
polymer NG
for theranostic
applications
Innate
fluorescence
Superparamagnetic
iron oxideNPs
(SPION)
Murine
model and
HeLa cells
[23]
Hyperthermia effect
Responsive
hyaluronic
acid-gold
clusters
hybrid NG
theranostic
system
Gold NPs DOX A549,
NIH3T3
and H22
cell lines
[24]
H22 tumor-
bearing
mice
Continued
Theranostic nanogels: design and applications 33](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-44-2048.jpg)
![The modification of functional groups in polymers is very common in the designing
of theranostic systems as it improves their properties for specific purposes. The design
and synthesis of NGs with diverse chemical compositions allows the incorporation of
various functional groups which are able to bind molecules of interest that provide
certain properties to the system [13]. In this sense, the interest in developing multifunc-
tional NGs which combine different properties has gained attention in the last years. In
a previous study, an alginate-based multifunctional theranostic prodrug NG was
designed with potential for tumor diagnosis and chemotherapy [21]. For this purpose,
the NG was prepared by cross-linking the folate-terminated PEG (FA-PEG-NH2) and
rhodamine B (RhB)-terminated PEG (RhB-PEG-NH2) modified oxidized alginate
with cystamine, following conjugation with DOX. The folate-receptor-mediated tar-
geting and pH/reduction dual responsive intracellular triggered a desirable release of
DOX allowing the killing of cancer cells. In addition, due to the RhB groups, the
NGs expressed strong fluorescence only in acidic media, similar to tumor microenvi-
ronment, therefore being optimum systems for real-time and noninvasive location
tracking to cancer cells.
When designing theranostic platforms, several strategies can be combined with the
objective of increasing the specificity of the system. The stimuli-responsive property is
desirable in theranostic platforms. In “smart” nanocarriers, the release of the encapsu-
lated bioactive agent can be triggered by various stimuli (temperature, pH, enzymes,
redox, hypoxia environment, etc.). In order to improve the efficacy of these systems
for cancer therapy, the incorporation of receptors-mediated cancer cell uptake is
Table 2.1 Theranostic NGs platforms using optical imaging modality for diagnostic
function.dcont’d
Theranostic
NG design Imaging agent
Therapeutic
agent/method
In vitro/
in vivo
model References
Fucoidan-based
theranostic
NG
Chlorin e6 Fucoidan HT1080
human
fibrosar
coma cell
line
[25]
Male BALB/
c nude
mice
Octreotide
conjugated
fluorescent
PEGylated
polymeric NG
for theranostic
applications
Innate
fluorescence
DOX HeLa cells [17]
Mice
DOX, doxorubicin; NG, nanogel; NPs, nanoparticles; PEG, polyethylene glycol
34 Design and Applications of Theranostic Nanomedicines](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-45-2048.jpg)
![considered another good strategy. In this sense, Lin et al. [24] synthetized a responsive
hyaluronic acid-gold clusters hybrid NG theranostic system with the ability of
responding to the reducing microenvironment, activating tumor targeting and light
traceable cancer therapy. The NGs were prepared by copolymerization in aqueous me-
dium of hyaluronic acid (HA) with vinyl group and cystamine bisacrylamide (CBA).
Then, the multifunctional mHA-gold clusters hybrid NGs (mHA-GC hybrid NGs)
were obtained by in situ reduction of gold salts in the HA NGs. The highly selective
cancer cells uptake and intratumoral accumulation of the NGs were demonstrated by
their fluorescence tracking. The drug release was triggered by the massive glutathione
(GSH) production in cancer cells which allowed disassembly of the NG. Moreover, the
antitumor activity of DOX was evidenced by tumor cell suppression through both
in vitro an in vivo studies. These findings suggested the targeted drug delivery and con-
trol release of antitumor drug with light-traceable monitoring abilities of these plat-
forms in cancer treatment. In another study performed by Cho et al. [25], a
fucoidan-based theranostic NG (CFN-gel) was synthetized to achieve activatable
NIR fluorescence imaging of tumor site and enhanced photodynamic therapy (PDT)
(Fig. 2.4). The CFN-gel had affinity for P-selectin, which is overexpressed on the sur-
face of tumor neovascular endothelial cells, thus providing an enhanced targeting. Due
to its aggregation-induced self-quenching in response to redox potential, this system
recovered its photoactivity only after internalization into cancer cells, enabling a selec-
tive NIR fluorescence imaging and an enhanced photodynamic of tumors. The CFN-
gel also showed antitumor effect in the absence of light treatment in vivo as fucoidan
Figure 2.4 Schematic illustration of CFN-gel and its mode of action. EPR, enhanced
permeation and retention.
Adapted from Cho MH, Li Y, Lo PC, Lee H, Choi Y. Fucoidan-based theranostic nanogel for
enhancing imaging and photodynamic therapy of cancer. Nano-Micro Lett [Internet] 2020;
12(1):1e15. Available from https://doi.org/10.1007/s40820-020-0384-8.
Theranostic nanogels: design and applications 35](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-46-2048.jpg)
![can inhibit the binding of the vascular endothelial growth factor (VEGF), a key angio-
genesis promoting molecule, to its cell membrane receptor. The observations indicated
that the CFN-gel could be a new theranostic material for imaging and treating cancer.
In order to exert the diagnostic function, theranostic systems need to include
different materials such as iron oxide NPs, quantum dots, gold NPs, and others
[26]. Superparamagnetic iron oxide NPs (SPION) are able to perform both imaging
and therapy through MRI and hyperthermia effect [27]. SPION are capable to destroy
cancer cells through the conversion of an alternating high-frequency magnetic field
into thermal energy, a phenomenon known as magnetic hyperthermia [23]. Taking
advantage of these properties, Vijayan et al. [23] created a magneto-fluorescent hybrid
polymer NG for theranostic applications. The system consisting of a core-shell
morphology (SPION core and PEG shell) revealed good cancer fluorescence capability
and exerted hyperthermia effect evidenced by the cancer cells lysis. In addition, the
NG was assessed using a murine model showing good NIR imaging capability and
demonstrating promising future potential for cancer theranostic applications.
2.4.2 Magnetic resonance imaging
The use of magnetic resonance imaging (MRI) as a tool for diagnostic component has
also been studied for theranostic applications. Although this tool provides low ionizing
radiation exposure, high anatomical resolution and great soft tissue resolution, it pre-
sents certain disadvantages such as low sensitivity and poor contrast that limit its use in
cancer diagnostic [28]. The use of contrast agents in MRI is highly used to overcome
these problems as they can alter the relaxation times of protons in different organs by
their involvement with the external magnetic field [29]. In MRI, the contrast agents
more commonly used are gadolinium (Gd) chelates and iron oxide particles such as
SPION [19]. Sometimes, the use of contrast agent aggregates does not provide a pre-
cise imaging of the tumor due to their low molecular weight, being therefore necessary
large doses that significantly increase the risk of systemic toxicity [15]. These draw-
backs can be solved by encapsulating or chelating the contrast agents in NPs. In
this sense, recent investigations have been focused in developing of theranostic NGs
using MRI techniques (Table 2.2).
Peng et al. [30] designed a hybrid NG with magnetic and dual responsive proper-
ties consisting in an alginate coated SPION system. The alginate coating responded
to high concentration of GSH and acidic microenvironment of tumor cells, while the
SPION core provided MRI properties. In addition, the anticancer drug DOX was
encapsulated into the system. The NGs exhibited magnetic-targeted characteristics,
high drug loading capacity, co-triggered release behavior, high toxicity to tumor cells
and MRI functions. The authors concluded that these systems have great potential as
tumor-targeting nano-theranostic agents for simultaneous MRI and efficient anti-
tumor treatment. In a similar way, Chen et al. [32] created a multifunctional system
consisting in a hybrid FeeO4-poly(acrylic acid) NG for both drug delivery and MRI.
The hybrid NGs showed high drug (DOX) loading capacity and sustained drug
release. The NGs were able to penetrate the plasma membrane of SH-SY5Y cells,
suggesting their good attributes as carriers for drug delivery. Moreover, the cyclic
36 Design and Applications of Theranostic Nanomedicines](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-47-2048.jpg)
![RGD peptide was conjugated to the surface of the NG to target integrin avb3, a pro-
tein expressed on cancer cell membranes. Besides, the ability of cyclic RGD-coated
NGs to target integrin avb3 was assessed in vivo by MRI with mice bearing-
hepatocarcinoma tumors. MRI studies revealed that the NGs reach the tumor site
showing the specificity of the particle targeting in vivo. The results suggested that
the hybrid NG presents suitable properties for practical applications in simultaneous
drug delivery, tumor diagnostics and targeted therapy. Zou et al. [34] also designed a
polyethylenimine (PEI)-based hybrid NG incorporated with ultrasmall iron oxide NP
and DOX (Fe3O4/PEI-Ac NGs/DOX) for MRI-guided chemotherapy of tumor
(Fig. 2.5). The hybrid NGs showed pH-dependent release of DOX and were taken
up by cancer cells in vitro. Moreover, they exerted an inhibitory effect on tumor
growth which was evidenced by MRI.
Table 2.2 Theranostic NGs systems using magnetic resonance imaging for diagnostic purposes.
Theranostic platform
Imaging
agent
Therapeutic
agent Application References
Novel dual responsive
alginate-based
magnetic NGs for
oncotheranostics
SPION DOX HepG cells [30]
Magnetic and
thermoresponsive
NGs for NIR-triggered
chemotherapy
Iron
oxide
NPs
DOX Murine model
and HeLa cells
[31]
Hybrid Fe-O4-
poly(acrylic acid) NG
for both drug delivery
and MRI
SPION DOX Murine hepatic
carcinoma
H22 cells and
SH-SY5Y
cells
[32]
Core-shell NPs for MRI-
guided
thermochemotherapy
Iron
oxide
NPs
DOX Human ovary
cancer cell
(HAC-2) and
mice bearing
ovarian cancer
[33]
Polyethylenimine NG
incorporated with
ultrasmall iron oxide
NPs and DOX for
MRI-guided
chemotherapy of
tumor
Fe3O4
NPs
DOX 4T1 cancer cells
(mammary
carcinoma cell
line from the
mammary
gland tissue of
a mouse)
[34]
4T1 tumor-
bearing mice
DOX, doxorubicin; SPION, superparamagnetic iron oxide NPs.
Theranostic nanogels: design and applications 37](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-48-2048.jpg)
![Magnetic hyperthermia as a new thermotherapy facilitates the treatment of deep tu-
mors at a local level because the magnetic particles only produce the heat in a specific
area and the alternate magnetic field can penetrate deep within the body [33]. Thus, the
implementation of MRI-guided magnetic termochemotherapy appears to be a novel
technique that can be used to improve the therapeutic effect. In a previous work, Hay-
ashi et al. [33] developed a core-shell system where the magnetic iron oxide NPs were
entrapped into the polymer network. The NG system accumulated in abdomen tumors
facilitating their visualization by MRI. The exposure of the NG system to an alter-
nating magnetic field induced heat generation allowing the release of the entrapped
drug within the tumor and causing their growth inhibition. These findings indicated
that core-shell magnetic termochemotherapy could exert better therapeutic efficacy
that both magnetic hyperthermia and chemotherapy as individual treatments. Biglione
et al. [31] designed a magnetic thermoresponsive NG for NIR triggered chemotherapy.
The system consisted of an NG with dispersed iron oxide NPs on its polymer (oligo-
ethylene glycol methacrylate) network. Because the iron oxide NPs are capable of
transducing NIR light into heat and can be used as MRI contrast agents due to their
paramagnetic properties, the system showed a successful NIR-triggered chemo-
therapy. The system produced hyperthermia created by the light-to heat conversion
of the magnetic particles exposed to NIR irradiation and showed an antiproliferative
effect on HeLa cells in vitro due to the release of the encapsulated drug (DOX). In
addition, the NIR-chemotherapy effect of the system was demonstrated through
in vivo studies by MRI. The observations indicated that this hybrid NG can be used
for photothermal therapy as well as for MRI, therefore being good candidate for thera-
nostic devices.
Figure 2.5 Schematic representation of the synthesis of Fe3O4/PEI-Ac NGs/DOX complexes
for MRI-guided chemotherapy of tumors. BIS, N,N0-methylene-bis(acrylamide); EDC, 1-
ethyl-3-(3-(dimethylamino)propyl) carbodiimide hydrochloride.
Adapted from Zou Y, Li D, Wang Y, Ouyang Z, Peng Y, Tom
as H, et al. Polyethylenimine
nanogels incorporated with ultrasmall iron oxide nanoparticles and doxorubicin for MR
imaging-guided chemotherapy of tumors. Bioconjug Chem 2020;31(3):907e15.
38 Design and Applications of Theranostic Nanomedicines](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-49-2048.jpg)
![2.4.3 Ultrasound imaging
Ultrasound imaging (USI) has become a very attractive diagnostic method due to its
low cost and multiple advantages. USI is a real-time noninvasive method in which
the tissues reflect the transmitted sound waves and are converted to pictures by a con-
verter [15]. High intensity focused ultrasound (HIFU) is a safe and feasible technique
that can be employed as a novel theranostic tool for simultaneous imaging and site-
specific therapy [35]. HIFU is capable of inducing tissue necrosis through the conver-
sion of US energy to hyperthermia when focused [35]. The use of NPs loading with
US-sensitive molecules is commonly used to intensify the HIFU ablation effects on
tumors. Moreover, the aggregation of the NPs in tumor tissue promotes the acoustic
impedance and favors the USI [35]. Recently, a ternary inorganic-supramolecular-
polymeric NG was designed as a multifunctional nanotheranostic agent for combined
USI and imaging-guided HIFU therapy [36]. The multifunctional NGs were synthe-
tized by the in situ amidation-fueled self-assembly and laccase-mediated post-cross-
linking and loaded with DOX and perfluorohexane as therapeutic and US-sensitive
guest molecules (MSN-GII-PFH). In vitro evaluation demonstrated that the NGs can
be taken up by the tested cells (human liver hepatocellular carcinoma SMMC-7721
cells and human hepatocytes LO2 cells) and show low cytotoxicity, being therefore
suitable for in vivo USI and US-mediated chemotherapy. In vivo studies performed
in rabbits bearing-liver tumor indicated that the system responded efficiently to US
irradiation as evidenced by good USI (Fig. 2.6). In addition, the high efficacy of the
Figure 2.6 In vivo applications: The schematic illustration of the USI-guided HIFU therapy
(a) and US images (b), as well as the corresponding average gray values (c) of VX2 tumors in
rabbit livers before and after intravenous injection of MSN-GII-PFH at various time intervals
(30 min, 1 h) and post therapy. Each column is the average of three experiments (** and ***
represent significant differences in the average gray values by comparing the different samples
at P 0.01 and P 0.001). The tumors are marked by yellow arrows.
Adapted from Wang X, Qiao L, Yu X, Wang X, Jiang L, Wang Q. Controllable formation of
ternary inorganic-supramolecular-polymeric hydrogels by amidation-fueled self-assembly and
enzymatic post-cross-linking for ultrasound theranostic. ACS Biomater Sci Eng 2019;5(11):
5888e96.
Theranostic nanogels: design and applications 39](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-50-2048.jpg)
![USI-guided HIFU therapy was evidenced by the observed enhanced imaging after tu-
mor ablation. These findings demonstrated the potential application of this hybrid NG
as nanotheranostic carrier for US-guided HIFU therapy.
One of the main limitations of USI is the poor image contrast that stems from
similar acoustic impedances between normal and abnormal soft tissues [37]. There-
fore, in order to differentiate between normal and abnormal tissues, the use of US
contrast agents to enhance US image represents a good alternative [35]. In this sense,
the use of nanoscale gas-generating chemical systems capable of stimulus-responsive
inflation to microbubbles has been employed as an echogenic strategy for enhancing
USI. Heo et al. [37] reported a peroxamide-based US contrast agent as a H2O2-respon-
sive gas (CO2)-generating system for diagnostic USI of inflammatory diseases. For this
purpose, the authors prepared a hydrolytic degradation-resistant peroxamide NG. The
interior of the peroxamide-concentrated NG served as a catalytic reactor for the H2O2-
responsive gas generation as well as a gas reservoir capable of nano-to-micro inflation.
The system could enhance the US contrast in response to H2O2 allowing to perform
diagnostic USI of H2O2-overproducing inflammatory disease in mouse models.
2.4.4 Photoacoustic imaging
Photoacoustic imaging (PAI) has become a promising technique for disease diagnosis
due to its excellent spatial resolution and high optical contrast. In PAI, the tissue is
exposed to a laser light, and it absorbs the light causing local heating and undergoes
thermoelastic expansion, resulting in US waves, a phenomenon known as photoacous-
tic effect [38]. The photoacoustic conversion is proportional to the optical absorption;
therefore, the individual tissue constituents that absorb light at different wavelengths
can be selectively imaged with PAI [38]. Photothermal therapy (PTT) is a novel
method used in cancer therapy that can destruct cancer cells without damaging the sur-
rounding healthy tissues [39] by the use of photothermal agents that convert light en-
ergy into heat under laser radiation [40]. The photothermal agents can be used as
contrast agents for PAI as they can absorb the pulsed light and the US waves generated
can be detected using a special transductor [41]. Several photothermal agents are used
in PAI-guided PTT including metal or inorganic NPs [42], conducting polymers
[43,44], and other small molecules such as cyanine and porphyrin [45]. These agents
are usually encapsulated to protect their stability and increase their circulation time
in vivo.
Zhou et al. [43] developed a polyaniline-loaded polyglutamic acid NG as a platform
for PAI-guided tumor PTT (g-PGA/Cys@PANI NGs). The NGs exhibited excellent
NIR absorbance providing good PAI contrast and photothermal conversion capacity.
An in vitro study showed that the cells (4T1) treated with the NGs and exposed to irra-
diation significantly reduced their viability, indicating their ability as photothermal
agents. Besides, the efficacy of the system was assessed by in vivo studies on a xeno-
grafted tumor model, observing good tumor PAI performance. The application of laser
irradiation to rats injected with the NGs resulted in heat generation in the tumor region,
suggesting the potential of these systems in PPT applications. Similarly, a thermo-
responsive NG loaded with the photothermal transducing polymer polypyrrole for
40 Design and Applications of Theranostic Nanomedicines](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-51-2048.jpg)
![combinational photothermal and chemotherapy along with PAI was designed by The-
une et al. [44]. The synthetized NGs showed a dual-response for temperature and NIR
light where the generated heat under irradiation exposure served for triggering the
thermo-responsive network and for photothermal ablation of cancer. The NGs also
allowed the determination of their biodistribution after administration ex vivo due to
their abilities as photoacoustic contrast agents. Finally, in vivo studies demonstrated
that the NGs efficiently inhibited the tumor growth due to the combination of chemo-
therapeutic and photothermal treatment.
2.4.5 Positron emission tomography
Positron emission tomography (PET) imaging and SPECT are both radionuclide im-
aging techniques [15]. As imaging tool, PET is commonly used in oncology,
neurology, and cardiology. Because this technique uses gamma rays which have the
highest energy among imaging methods, it possesses high sensitivity providing excel-
lent visualization and quantification of disease markers [19]. The tracers used for PET
imaging usually include organic molecules such as 18
F and 11
C or metal radionuclide
such as copper-64, yttrium-86, zirconium-89, and others [19] (Table 2.3). The radio-
nuclide 99
Tc has shown good performance for SPECT imaging because it provides
higher imaging resolution in comparison with other molecules such as 131
I [46,47].
In a previous study, Zhao et al. [48] elaborated a theranostic nanocomplex with
enhanced blood-brain barrier penetrability and tumor-targeting efficiency for glioma
SPECT imaging and anticancer drug delivery. The system was designed using
branched PEI which was conjugated with glioma-targeting peptide chlorotoxin
(CTX) and the radionuclide 99m
Tc, and finally loaded with DOX. The nanosystem
showed targeting specificity and therapeutic effect of DOX toward glioma cells
in vitro and in vivo using a subcutaneous tumor mouse model. The radiolabeling of
the NG with 99m
Tc allowed the visualization of drug accumulation in tumors of
glioma-bearing mice and the DOX delivery into the brains of rats through SPECT im-
aging. The results demonstrated the potential of this nanosystem for facilitating
glioma-targeting SPECT imaging and chemotherapy. Among the organic tracers,
18
F (fluorodeoxyglucose) which is a glucose analog is frequently used for oncological
imaging because many tumors consume more glucose than surrounding tissues [49]. A
novel nanocomplex comprising alginate NG co-loaded with cisplatin and Au NPs was
designed by Mirrahimi et al. [50] for combined chemo-PTT. In vivo results using a
CT26 tumor-bearing mice demonstrated that the administration of the NGs caused
an evident tumor inhibition. The combined action of chemo-PTT suppressed the tumor
growth up to 95% and prolonged the survival rate of mice in comparison to the control
group. Moreover, the tracer 18
F was used to monitor the tumor metabolism by PET
imaging, and the results showed that the administration of the NGs along with laser
irradiation are capable of eradicating microscopic residual tumor to prevent cancer
relapse. With the results observed, it was concluded that these systems have potent
anticancer effect and may reduce considerably the side-effects associated to
chemotherapy.
Theranostic nanogels: design and applications 41](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-52-2048.jpg)
![2.4.6 X-ray computed tomography
X-ray computed tomography (CT) is a widely used noninvasive imaging modality in the
clinical field. It possesses high spatial resolution, high penetration providing precise
anatomical information with reconstructed tridimensional imaging [52,53]. Among the
contrast agents, more commonly used for CT imaging are iodinated small molecules
[15]. Iodixanol, a contrast agent frequently used in CT imaging, has low osmolality
and good tolerability [53]; however, it has nonspecific distribution and rapid renal clear-
ance post injection [54]. Nanosized CT contrast agents represent a good alternative to
avoid these limitations as they exhibit longer circulation time and site-specific accumula-
tion [55]. Zhu et al. [55] prepared a bioresponsive and fluorescent hyaluronic acid-
Table 2.3 Theranostic NGs platforms using positron emission tomography for diagnostic
purposes.
Theranostic
platform
Imaging
agent
Therapeutic
agent Application References
Thermo-
responsive
alginate NG
co-loaded
with Au NPs
and cisplatin
for combined
cancer
chemo-PTT
18
F Cisplatin CT26 tumor-bearing
mice (colon
adenocarcinoma)
[50]
PEI-based
theranostic
nanoplatform
for glioma-
targeting
SPECT
imaging and
anticancer
drug delivery
99m
Tc DOX Subcutaneous tumor
mouse model
[48]
Multifunctional
nanocarrier
based on
triblock
copolymer for
simultaneous
PET imaging
and
combination
therapy
Zr-89
and
Cu-64
Cisplatin, Ras
inhibitor
farnesylthio
salicylate
4T1 tumor bearing
mice
[51]
NG, nanogel; NPs, nanoparticles; PEI, polyethylenimine; PET, positron emission tomography; PTT, photothermal therapy;
SPECT, single-photon emission computed therapy.
42 Design and Applications of Theranostic Nanomedicines](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-53-2048.jpg)
![iodixanol NG for targeted X-ray CT imaging and chemotherapy of breast tumors. The
NGs loaded with paclitaxel showed fast GSH-responsive drug release. In vivo studies
showed that NGs prolonged the blood circulation time, enhanced drug accumulation
and tumor penetration in MCF-7 breast tumor-bearing mice, allowing a marked tumor
growth inhibition and survival rate of the mice. In addition, the administration of the
NGs via intratumoral or intravenous injection improved CT imaging of tumors compared
to iodixanol. A wide variety of nanoparticulate contrast agents including gold NPs, bis-
muth sulfide NPs and ytterbium-based NPs have been explored for CT imaging [56]. A
gold NP-loaded g-polyglutamic acid NG for tumor CT imaging was developed by
Zhouetal. [56].The NGs demonstratedexcellent propertiesfor application as aneffective
contrast agent for CT imaging in vitro and in vivo.
2.4.7 Multimodal imaging
In theranostics field, the development of multifunctional NGs systems that combines
different imaging modalities in a single platform have become a novel strategy used to
improve the sensitivity and detection limits of clinical diagnostics [23]. This strategy
takes advantage from the best attributes of each imaging agent and through their com-
bination allows the developing of novel systems with enhanced properties for diag-
nostic functions. Several NGs designs using multiple imaging modalities have been
reported in the literature with promising results (Table 2.4).
PTT employs the heat energy converted from NIR light to kill cancerous cells. The NIR
region is divided into two windows, the NIR-I ranging from 700 to 950 nm and the NIR-II
from 1000 to 1700 nm [66]. The light in the NIR-II window exhibits high maximum
permissible exposure and deep tissue penetration than the light from the NIR-I window
[67]. Therefore, PTT using the NIR-II window is preferable for the treatments. The appli-
cation of MRI as diagnostic function possesses some drawbacks regarding its poor sensi-
tivity that limits precision in diagnostics. Therefore, the incorporation of a second imaging
modality such as PAI that combines optical and USI properties results an excellent alter-
nativeto improvethe precisionof tumor imaging. In addition,most of photothermal agents
can also be used for PAI. Zhang et al. [57] prepared a Gd/CuS-loaded functional NG for
MR and PAI-guided tumor-targeted PTT (Fig. 2.7). The NGs were prepared by inverse
emulsion and their surface was functionalized with Gd(III) chelates, targeting ligand folic
acid (FA) through a polyethylene glycol (PEG) spacer and 1,3-propane-sultone. The func-
tionalized NGs (Gd/CuS@PEI-FA-PS NGs) showed excellent NIR-II absorption, photo-
thermal conversion efficiency, and folic acid-mediated targeting specificity to cancer cells
overexpressing FA receptor. The dual-mode imaging of the NGs was assessed in vivo with
a transplanted KB tumor model observingtheir capability for MR/PA dual-mode imaging-
guided targeted PTT under light irradiation. Moreover, the results demonstrated the effi-
cacy of the PTT of the system as evidenced by the complete tumor eradication in the group
treated with the NGs after 24 days of photothermal treatment. Although PA/NIR-II dual
mode imaging provides high sensitivity and good resolution morphological structure,
the anatomic information provided is limited [68]. In order to avoid this limitation, Hu
etal.[60]incorporatedMRIasathirdimagingtechniqueintoanNGsystem.Theydesigned
a water-soluble Gd-chelated conjugated polymer-based theranostic nanomedicine (PFTQ-
PEG-Gd NPs) for in vivo tri-mode PA/MR/NIR-II imaging-guided tumor PTT. The
Theranostic nanogels: design and applications 43](https://image.slidesharecdn.com/24584745-250519223059-8ad1ee9c/75/Design-And-Applications-Of-Theranostic-Nanomedicines-Somasree-Ray-54-2048.jpg)
Design And Applications Of Theranostic Nanomedicines Somasree Ray
- 1. Design And ApplicationsOf Theranostic Nanomedicines Somasree Ray download https://ebookbell.com/product/design-and-applications-of- theranostic-nanomedicines-somasree-ray-49169490 Explore and download more ebooks at ebookbell.com
- 2. Here are somerecommended products that we believe you will be interested in. You can click the link to download. Design And Applications Of Nature Inspired Optimization Contribution Of Women Leaders In The Field Dipti Singh https://ebookbell.com/product/design-and-applications-of-nature- inspired-optimization-contribution-of-women-leaders-in-the-field- dipti-singh-48847702 Design And Applications Of Emerging Computer Systems 1st Edition Weiqiang Liu https://ebookbell.com/product/design-and-applications-of-emerging- computer-systems-1st-edition-weiqiang-liu-54878778 Design And Applications Of Nanomaterials For Sensors 1st Edition Jorge M Seminario Eds https://ebookbell.com/product/design-and-applications-of- nanomaterials-for-sensors-1st-edition-jorge-m-seminario-eds-4936018 Design And Applications Of Coordinate Measuring Machines Kuangchao Fan https://ebookbell.com/product/design-and-applications-of-coordinate- measuring-machines-kuangchao-fan-50654884
- 3. Design And ApplicationsOf Nanostructured Polymer Blends And Nanocomposite Systems 1st Edition Chandrasekharakurup https://ebookbell.com/product/design-and-applications-of- nanostructured-polymer-blends-and-nanocomposite-systems-1st-edition- chandrasekharakurup-5433270 Design And Applications Of Nanoparticles In Biomedical Imaging 1st Edition J W M Bulte https://ebookbell.com/product/design-and-applications-of- nanoparticles-in-biomedical-imaging-1st-edition-j-w-m-bulte-5702362 Design And Applications Of Hydrophilic Polyurethanes Edited By Nobuhiko Yui https://ebookbell.com/product/design-and-applications-of-hydrophilic- polyurethanes-edited-by-nobuhiko-yui-1199610 Design And Applications Of Adaptive Impedance Converters Lei Wang https://ebookbell.com/product/design-and-applications-of-adaptive- impedance-converters-lei-wang-60613498 Design And Applications Of Hydroxyapatitebased Catalysts Doan Pham Minh https://ebookbell.com/product/design-and-applications-of- hydroxyapatitebased-catalysts-doan-pham-minh-46233048
- 6. Woodhead Publishing Seriesin Biomaterials Design and Applications of Theranostic Nanomedicines Edited by Somasree Ray Professor, Department of Pharmaceutics, Gupta College of Technological Sciences, Asansol, West Bengal, India Amit Kumar Nayak Professor, Department of Pharmaceutics, Seemanta Institute of Pharmaceutical Sciences, Jharpokharia, Mayurbhanj, Odisha, India
- 7. Woodhead Publishing isan imprint of Elsevier 50 Hampshire Street, 5th Floor, Cambridge, MA 02139, United States The Boulevard, Langford Lane, Kidlington, OX5 1GB, United Kingdom Copyright © 2023 Elsevier Ltd. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Details on how to seek permission, further information about the Publisher’s permissions policies and our arrangements with organizations such as the Copyright Clearance Center and the Copyright Licensing Agency, can be found at our website: www.elsevier.com/permissions. This book and the individual contributions contained in it are protected under copyright by the Publisher (other than as may be noted herein). Notices Knowledge and best practice in this field are constantly changing. As new research and experience broaden our understanding, changes in research methods, professional practices, or medical treatment may become necessary. Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds, or experiments described herein. In using such information or methods they should be mindful of their own safety and the safety of others, including parties for whom they have a professional responsibility. To the fullest extent of the law, neither the Publisher nor the authors, contributors, or editors, assume any liability for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the material herein. ISBN: 978-0-323-89953-6 For information on all Woodhead Publishing publications visit our website at https://www.elsevier.com/books-and-journals Publisher: Matthew Deans Acquisitions Editor: Sabrina Webber Editorial Project Manager: Andrea Gallego Ortiz Production Project Manager: Prem Kumar Kaliamoorthi Cover Designer: Matthew Limbert Typeset by TNQ Technologies
- 8. Dedicated to ourbeloved teacher Prof. (Dr.) Biswanath Sa.
- 9. List of contributors BandarE. Al-Dhubiab Department of Pharmaceutical Sciences, College of Clini- cal Pharmacy, King Faisal University, Al-Ahsa, Saudi Arabia Ashique Al Hoque Department of Pharmaceutical Technology, Jadavpur Univer- sity, Kolkata, West Bengal, India Abul Kalam Azad Faculty of Pharmacy, Pharmaceutical Technology Unit, AIMST University, Kedah, Malaysia Jaya Bajpai Bose Memorial Research Lab, Department of Chemistry, Government Autonomous Science College Jabalpur, Madhya Pradesh, India A.K. Bajpai Bose Memorial Research Lab, Department of Chemistry, Government Autonomous Science College Jabalpur, Madhya Pradesh, India Saad Bakrim Laboratory of Molecular Engineering, Valorization and Environment, Department of Sciences and Techniques, Polydisciplinary Faculty of Taroudant, Ibn Zohr University, Taroudant, Souss-Massa, Morocco Abdelaali Balahbib Laboratory of Biodiversity, Ecology, and Genome, Faculty of Sciences, Mohammed V University in Rabat, Rabat, Rabat-Salé-Kénitra, Morocco Souvik Basak Dr. B.C. Roy College of Pharmacy & Allied Health Sciences, Dr. Meghnad Saha Sarani, Bidhan Nagar, Durgapur, West Bengal, India Anindita Behera School of Pharmaceutical Sciences, Siksha ‘O’ Anusandhan Deemed to be University, Bhubaneswar, Odisha, India Uttam Kumar Bhattacharyya Gupta College of Technological Sciences, Asansol, West Bengal, India Abdelhakim Bouyahya Laboratory of Human Pathologies Biology, Department of Biology, Faculty of Sciences, and Genomic Center of Human Pathologies, Faculty of Medicine and Pharmacy, Mohammed V University in Rabat, Rabat, Morocco Elizabeth Carvajal-Millan Biopolymers, Research Center for Food and Develop- ment, CIAD A.C., Carretera Gustavo E. Astiazaran Rosas No. 46, Hermosillo, Sonora, Mexico
- 10. Samrat Chakraborty Departmentof Pharmaceutical Technology, Jadavpur Uni- versity, Kolkata, West Bengal, India; Gupta College of Technological Sciences, Asan- sol, West Bengal, India Apala Chakraborty Department of Pharmaceutical Technology, Jadavpur Univer- sity, Kolkata, West Bengal, India Imane Chamkhi Centre GEOPAC, Laboratoire de Geobiodiversite et Patrimoine Naturel Université Mohammed V de, Institut Scientifique Rabat, Rabat, Rabat-Salé- Kénitra, Morocco Pronobesh Chattopadhyay Division of Pharmaceutical Technology, Defence Research Laboratory, Tezpur, Assam, India Rashmi Choubey Bose Memorial Research Lab, Department of Chemistry, Gov- ernment Autonomous Science College Jabalpur, Madhya Pradesh, India Hira Choudhury Department of Pharmaceutical Technology, School of Pharmacy, International Medical University, Kuala Lumpur, Malaysia Avik Das Gupta College of Technological Sciences, Asansol, West Bengal, India Monodip De Dr. B.C. Roy College of Pharmacy & Allied Health Sciences, Dr. Meghnad Saha Sarani, Bidhan Nagar, Durgapur, West Bengal, India Piyali Dey Faculty of Pharmaceutical Science, Assam down town University, Guwahati, Assam, India; Piyali Dey, Assistant Professor, Assam down town Univer- sity, Guwahati, Assam, India Ibrahim M. El-Sherbiny Nanomedicine Research Laboratories, Center for Materi- als Science, Zewail City of Science and Technology, Giza, Egypt Naoual Elmenyiy Laboratory of Physiology, Pharmacology and Environmental Health, Faculty of Science, University Sidi Mohamed Ben Abdellah, Fez, Fez- Mekn es, Morocco Nasreddine El Omari Laboratory of Histology, Embryology, and Cytogenetic, Fac- ulty of Medicine and Pharmacy, Mohammed V University in Rabat, Rabat, Rabat- Salé-Kénitra, Morocco Ouadie Mohamed El Yaagoubi Laboratory of Biochemistry, Environment and Agri-Food (URAC 36)dFaculty of Sciences and TechniquesdMohammedia, Hassan II University Casablanca, Casablanca, Casablanca-Settat, Morocco Muhammad Asim Farooq Drug Delivery, Disposition, and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia Bapi Gorain School of Pharmacy, Faculty of Health and Medical Science, Taylor’s University, Subang Jaya, Selangor, Malaysia; Department of Pharmaceutical Sciences and Technology, Birla Institute of Technology, Mesra, Ranchi, India xiv List of contributors
- 11. Maryam Hakkour Laboratoryof Biodiversity, Ecology, and Genome, Faculty of Sciences, Mohammed V University in Rabat, Rabat, Rabat-Salé-Kénitra, Morocco Md Saquib Hasnain Department of Pharmacy, Palamau Institute of Pharmacy, Chianki, Daltonganj, Jharkhand, India Amna Jabeen Faculty of Pharmacy, Lahore College of Pharmaceutical Sciences, Lahore, Punjab, Pakistan Suman Mallik Narayana Super Speciality Hospital, Kolkata, West Bengal, India Amira Mansour Nanomedicine Research Laboratories, Center for Materials Sci- ence, Zewail City of Science and Technology, Giza, Egypt Mayra A. Mendez-Encinas Department of Chemical Biological and Agropecuary Sciences, University of Sonora, Avenida Universidad e Irigoyen, Caborca, Sonora, Mexico Biswajit Mukherjee Department of Pharmaceutical Technology, Jadavpur Univer- sity, Kolkata, West Bengal, India Anroop B. Nair Department of Pharmaceutical Sciences, College of Clinical Phar- macy, King Faisal University, Al-Ahsa, Saudi Arabia Amit Kumar Nayak Department of Pharmaceutics, Seemanta Institute of Pharma- ceutical Sciences, Jharpokharia, Mayurbhanj, Odisha, India Santwana Padhi KIIT Technology Business Incubator, KIIT Deemed to be Univer- sity, Bhubaneswar, Odisha, India Anjali Pal Bose Memorial Research Lab, Department of Chemistry, Government Autonomous Science College Jabalpur, Madhya Pradesh, India Parthasarathi Panda Dr. B.C. Roy College of Pharmacy Allied Health Sciences, Dr. Meghnad Saha Sarani, Bidhan Nagar, Durgapur, West Bengal, India Brahamacharry Paul Department of Pharmaceutical Technology, Jadavpur Uni- versity, Kolkata, West Bengal, India Ng Yen Ping Faculty of Pharmacy, Clinical Pharmacy Unit, AIMST University, Kedah, Malaysia Shilpi Rawat Bose Memorial Research Lab, Department of Chemistry, Government Autonomous Science College Jabalpur, Madhya Pradesh, India Somasree Ray Gupta College of Technological Sciences, Asansol, West Bengal, India Malini Sen Gupta College of Technological Sciences, Asansol, West Bengal, India Ramkrishna Sen Department of Pharmaceutical Technology, Jadavpur University, Kolkata, West Bengal, India List of contributors xv
- 12. Shalmoli Seth GuptaCollege of Technological Sciences, Asansol, West Bengal, India Natalie Trevaskis Drug Delivery, Disposition, and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia Dickson Pius Wande Department of Pharmaceutics and Pharmacy Practice, School of Pharmacy, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania xvi List of contributors
- 13. Preface In the recentscenario, theranostic nanomedicines facilitate multifunctional activities including diagnosis and therapy of various diseases. Over the past few years, numerous therapeutic and diagnostic agents are being delivered at the targeted site with minimum side effects and proper therapeutic/diagnostic action(s) for an extended period of time. An ideal theranostic nanomedicine not only genuinely diagnoses and detects any disease at its preliminary stage but also provides the most favorable treat- ment. This book entitled “Design and Applications of Theranostic Nanomedicines” covers the recent innovations in the designing of nanomedicines composed of natural and/or synthetic polymers and inorganic nanomaterials with their helpful theranostic applications. It also provides a concise overview of utility of the amalgamated actions of these theranostic nanostructures as nanomedicines in the pharmaceutical and health- care industry. This book also acts as an important reference for the readers and pro- vides detail information about targeted delivery of nanotheranostics and how they work as both diagnostic and therapeutic tools in treating complex diseases. This book is a collection of 15 chapters presenting different key topics related to nanomedicines, their designing and theranostic applications by the leading academi- cians, scientists, and researchers across the world. A concise sketch on each chapter contents has been presented for the readers to provide a clear overview of this book. Chapter 1 entitled “Theranostic nanostructures as nanomedicines: Benefits, costs, and future challenges” focuses on the current research on nanostructure- based therapeutics and diagnostics systems, including benefits, costs, and future challenges. Chapter 2 entitled “Theranostic nanogels: Design and applications” describes the designs and applications of theranostic nanogels with a particular emphasis in discus- sing the imaging modality used for the diagnostic function. Chapter 3 entitled “Exosomes: A novel tool for diagnosis and therapy” highlights various features of exosomes, their roles in diagnosis, and therapeutic applications. Chapter 4 entitled “Engineered liposomes as drug delivery and imaging agents” reviews the development, progress, and applications of various engineered liposomes for delivery of drugs and imaging agents, individually or in combinations as theranostics. Chapter 5 entitled “Polymeric micelles for theranostic uses” addresses comprehen- sive discussions involving description and preparation of polymeric micelles, mecha- nism of drug release from micelles, and their potential theranostic applications specially in different stages of cancer therapy.
- 14. Chapter 6 entitled“Dendrimers: An effective drug delivery and therapeutic approach” highlights the usefulness of dendritic structures and their potential applica- tions in the treatment of various diseases. Chapter 7 entitled “Nanocochleates: A novel lipid-based nanocarrier system for drug delivery” covers recent advancements in nanocochleate-based drug delivery sys- tems with multiple aspects of nanocochleates such as their chemistry, components, mechanism of actions, methods of preparation, stability, advantages, characterization, applications, and current commercial status. Chapter 8 entitled “Theranostic applications of nanoemulsions in pulmonary dis- eases” deals with comprehensive discussions on the preparation and characterization of nanoemulsions, advantages and disadvantages of nanoemulsions, clearance of nanoemulsions, applications as novel theranostic tools (as nanoemulsion-based drug delivery systems and nanoemulsion-based diagnostics) in treatment/management of pulmonary diseases. Chapter 9 entitled “Polymeric nanoparticles as tumor-targeting theranostic plat- form” reviews different strategies developed for the application of polymeric nanopar- ticles for tumor-targeting diagnosis and therapy, with a closer look at the recent studies, and discusses how the strategic development has progressed throughout the years for the bench-to-market conversion of concept to commercialization. Chapter 10 entitled “Site-specific theranostic uses of stimuli responsive nanohy- drogels, design, and applications of theranostic nanomedicines” summarizes the importance of nanohydrogels’ response to the internal stimuli like pH, redox potential, etc., and external stimuli like temperature, light, magnetic field, etc., used for theranos- tic applications like delivery of drugs at the specific target sites with controlled release kinetics to tumor tissue and other disease conditions as well as disease diagnosis. Chapter 11 entitled “Ligand appended theranostic nanocarriers for targeted bloodebrain barrier” encompasses preliminary introduction of ligand-appended nanocarriers, their synthesis, characterization, and theranostic applications in crossing bloodebrain barrier with targeting abilities. The underlying challenges and future prospects have also been highlighted for stimulating advanced research in this area. Chapter 12 entitled “Nanotheranostics in CNS malignancy” presents a brief dis- cussion on various types of nanotheranostic agents that are used in the treatment of glioma and central nervous system (CNS) malignancy including gold nanoparticles, quantum dots, magnetic nanoparticles, mesoporous silica nanoparticles, solid lipid nanoparticles, dendrimers, liposomes, etc. Chapter 13 entitled “Application of nanotheranostics in cancer” reviews and eval- uates the advances in the developments of nanomedicines for the treatments, diagnos- tics, and theranostics of cancer. This chapter has also discussed the limitations in the provision of effective clinical usages of cancer nanotheranostics. Chapter 14 entitled “Self-assembled protein nanoparticles for multifunctional theranostic uses” discusses self-assembled protein-based nanomaterials in depth, with a focus on nanoparticles. Their multifunctional theranostic uses in delivering ther- apeutic medicines have also been explored with a practical discussion on how they might be useful as prospective techniques for efficient and safe delivery in the treat- ment/management of different diseases. xviii Preface
- 15. Chapter 15 entitled“Nanotheranostics: The toxicological implication” describes the relevance of the emergence of nanotheranostics as an effective branch of medicine with a specific focus on the toxicological concern. In addition, various in vitro and in vivo systems available for toxicity testing of nanotheranostic agents have also been outlined. We, the editors, are happy to express our special thanks to all the distinguished au- thors, who have contributed quality chapters in a timely manner. We especially express our gratitude to Elsevier Inc., Andre Gerhard Wolff, Sabrina Webber, Chiara Giglio, and Clodagh Holland-Borosh for their invaluable support in organization of the book-editing process. We would like to express our sincere thanks to Prem Kumar Kaliamoorthi (Senior Project Manager) for the development as well as production of finished book and Mohanraj Rajendran (Copyright Coordinator) for outstanding supports in obtaining copyright permissions. All the permissions for the reproduction of copyright contents and reprinting permission licenses from different copyright sour- ces have duly been gratefully acknowledged. Finally, we must appreciate our family members, all respected teachers, friends, colleagues, and students, for their continuous encouragements, inspirations, and moral supports during the book-editing process of this book. Together with all the contributing authors and the publisher, we will be extremely happy if our endeavor fulfills the needs of academicians, researchers, stu- dents, pharmaceutical experts, drug delivery formulators, polymer engineers, biomed- ical experts, and others. Prof. Somasree Ray Gupta College of Technological Sciences, India Prof. Amit Kumar Nayak Seemanta Institute of Pharmaceutical Sciences, India Preface xix
- 16. Theranostic nanostructures as nanomedicines:benefits, costs, and future challenges 1 Dickson Pius Wande1 , Natalie Trevaskis 2 , Muhammad Asim Farooq2 , Amna Jabeen3 and Amit Kumar Nayak4 1 Department of Pharmaceutics and Pharmacy Practice, School of Pharmacy, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania; 2 Drug Delivery, Disposition, and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia; 3 Faculty of Pharmacy, Lahore College of Pharmaceutical Sciences, Lahore, Punjab, Pakistan; 4 Department of Pharmaceutics, Seemanta Institute of Pharmaceutical Sciences, Jharpokharia, Mayurbhanj, Odisha, India 1.1 Introduction Nanomedicine is a developing field merging nanoscience, nanoengineering, and nano- technology with life sciences, revealing the valuable results for healthcare [1]. Although there are numerous nanomedicine applications, nanotechnology-based drug delivery systems and nanoimaging agents are of the utmost interest in medicine and pharmacy. “Theranostic” refers to the simultaneous integration of diagnosis and therapy [2]. Theranostic nanomedicines (or nanotheranostics) combine the use of theranostics with nanosized constructs that give multiple properties, such as targeted drug delivery, controlled release, greater transport efficiency via endocytosis, stimuli-responsive systems, and the amalgamation of therapeutic approaches, such as multimodality diagnosis and therapy [3]. Nanotheranostics unite the three stages in a single process, supporting early-stage diagnosis and treatment to overcome some of the issues with sensitivity and specificity of current medicines. An ideal nano- theranostic system should circulate for a long time in the body, provide sufficient release behavior, show tissue target specificity and penetration, imaging capability, and high target to background ratio [4]. Recently, novel and promising nanotherapeutic applications in the diagnosis and treatment have been revealed in various diseases, such as cancer [5,6]. However, the development of novel tools with improved imaging characteristics, which can lead to the early detection of diseases, is still of high importance. Aside from the ap- plications for diagnosis and nanotherapeutics are being increasingly designed and applied to treat a range of serious diseases [7]. At present, nanotheranostics are viewed as one of the key upcoming new strategies to tackle cancer, based on the postulation that if cancer progression can be hindered during an initial diagnostic procedure, the consequent anticancer therapy would be much easier since cancer growth will be Design and Applications of Theranostic Nanomedicines. https://doi.org/10.1016/B978-0-323-89953-6.00008-8 Copyright © 2023 Elsevier Ltd. All rights reserved.
- 17. retarded and theoverall cancer burden will be reduced [8,9]. The main challenge is to develop a system for molecular therapy capable of circulating in the bloodstream un- detected by the immune system of body and capable of recognizing the required target and signaling for effective drug delivery or gene silencing. As a result, nanotechnology plays a vital role in providing new types of nanotherapeutics for diseases that can pro- vide effective treatments with negligible side effects and high specificity [10,11]. Generally, theranostic nanomedicines can be engineered in several ways using tech- nologies, such as polymeric nanoparticles [12], carbon-based nanomaterials [13,14], lipid-based nanovesicles [15,16], protein-based nanostructures [17], dendrimers [18], ceramic nanostructures [19], metallic inorganic nanocarriers [20], and graphene quantum dots [21]. 1.2 Nanotechnology, nanoscale, and nanostructures Nanoscale science and technology often referred to as “nanoscience” or “nanotech- nology” are science and engineering carried out on the nanometer scale, that is, 10 9 m [22]. Nanotechnology is the field of research and innovation concerned with building materials, devices, and systems on the scale of atoms and molecules [23]. The US National Nanotechnology Initiative states: “The essence of nanotechnology is the ability to work at the molecular level, atom by atom, to create large structures with the fundamentally new molecular organization” [24]. The purpose is to exploit these properties by gaining control of structures and devices at atomic, molecular, and supramolecular levels to learn how to manufacture and use these devices, effi- ciently. The United States National Science Foundation defines nanoscience/nanotech- nology as studies dealing with materials and systems displaying three key properties: dimensiondat least one dimension from 1 to 100 nanometers (nm); processd designed with methodologies that show fundamental control over the physical and chemical attributes of molecular-scale structures; building block propertydthey can be combined to form larger structures [23e25]. In a general sense, nanoscience is quite natural in microbiological sciences consid- ering that the sizes of many bioparticles dealt with by the body (like enzymes, viruses, etc.) fall within the nanometer range [24]. Several nanoscale technologies are now available in the market. For example, specially prepared nanosized semiconductor crystals (quantum dots) are used as a tool for the analysis of biological systems [25]. Upon irradiation, these dots fluoresce specific colors of light based on their size. Quantum dots of different sizes can be attached to different molecules in a bio- logical reaction, allowing researchers to follow all the molecules simultaneously dur- ing biological processes with only one screening tool. These quantum dots can also be used as a screening tool for quicker, less laborious DNA and antibody screening than is possible with more traditional methods [22,26]. Nanostructures can be categorized depending on their size, shape, composition, sur- face characteristics, functionalization, and origin. The ability to predict the properties of nanostructures based on their classification is very useful to their applications [27]. 4 Design and Applications of Theranostic Nanomedicines
- 18. In terms ofshape, nanostructures can be classified into spherical, conical, spiral, cylin- drical, tubular, flat, hollow, or irregular in shape and can be from 1 to 100 nm in size [27,28]. Most nanostructured materials can be generally classified into four materials- based categories (organic, inorganic, composite, and carbon-based) [29]. Among these nanostructures, the use of a combination of more than one nanostructure to form a hybrid-nanostructure system is not uncommon [30]. Hybrid nanostructures are carefully designed with a combination of different mate- rials, which have different physiochemical properties and load different types of drugs. Hybrid nanostructures can also encompass nanoparticles that contain both structural (therapeutic) and functional (diagnostic) nanocomponents. The drug can be either encapsulated or bound to the surface of nanostructures depending on the physicochem- ical properties of the nanocarriers. These hybrid structures have a higher surface area. They are often engineered to increase the drug loading capacity. Sometimes, nanocar- riers can be designed to respond to specific endogenous or exogenous stimuli for controlled drug release [25]. Targeted drug delivery can be monitored externally by fluorescence dyes or intrinsic optical/magnetic/electrical properties of nanostructures. The development of hybrid nanostructures signifies an important step toward an effi- cient delivery of a range of therapeutics and imaging agents as hybrid nanostructures may allow the delivery of a combination of multiple drugs, DNA, RNAs, and diag- nostic agents [29]. 1.2.1 Carbonaceous-based hybrid nanostructures Carbon nanotubes are hydrophobic in nature and compromise the tubular nanostruc- tures with diameters in the order of less than 50 nm [31,32]. They display remarkable mechanical and optical properties [33,34]. These features have been harnessed in biomedical applications, such as photodynamic therapy [35], diagnostic imaging [36], and drug delivery [37]. Carbon nanotubes are essentially nontoxic, have high biocompatibility in the body, and are excreted via renal or biliary pathways depending on their surface chemistry [38]. They often have a longer blood circulation time than many other nanoparticles [39]. Graphene is an allotrope of carbon composed of a hexagonal network of a honey-comb structure made up of carbon atoms consisting of sp2-hybridized bonded carbon on a 2D planar surface [40,41]. The thickness of a graphene sheet is about 1 nm. Fullerenes (C60) are carbon-based molecules and spherical in morphology [42]. These are made up of carbon atoms held together via sp2 hybridization. Gener- ally, the other fullerenes (0D), such as C76, C80, and C240, are synthesized from larger numbers of carbon atoms [29]. Fullerenes are comprised of between 28 and 1500 car- bon atoms that form spherical structures [43]. Single-layer fullerenes have diameters up to 8.2 nm, while multilayer fullerenes have diameters between 4 and 36 nm. 1.2.2 Organic-based nanostructures Dendrimers, liposomes, and polymeric micelles are usually known as organic nano- structures [44]. These include nanostructures mostly made of organic materials. These Theranostic nanostructures as nanomedicines: benefits, costs, and future challenges 5
- 19. nanostructures are generallynontoxic and biodegradable in nature. Sometimes, these are sensitive to electromagnetic and thermal radiation. Organic nanostructures are most employed in pharmaceuticals for drug delivery systems because of their high biocom- patibility [44,45]. Dendrimers are prepared from monomers by either convergent or divergent step-growth polymerization [46]. The surface of a dendrimer encompasses several chains that can be modified to accomplish specific and specialized biochemical functions. Polymeric micelles possess amphiphilic block copolymers assembled to form nanoscopic core-shell structures [47,48]. Both the intrinsic and modifiable prop- erties of polymeric micelles make them well suited for the systemic delivery of poorly water-soluble medicines. 1.2.3 Inorganic-based nanostructures Inorganic nanostructures encompass structures that are not made from carbon-based or organic-based systems. Inorganic-based nanostructures have been of particular interest for bioimaging applications due to their high thermal conversion efficiency, ease of synthesis, and possible surface modifications [49]. These nanostructures include metal and metal oxide nanostructures. Metal-based and metal oxide-based nanostructures are commonly categorized as inorganic nanostructures. These nano- structures can be synthesized into metal nanostructures, such as palladium or gold, metal oxide nanostructures like titanium dioxide, and semiconductors, such as ce- ramics and silicon. Metal-based nanoparticles have fascinated scientists for over a century and are nowadays heavily utilized in biomedical and material sciences. Almost all metals can be synthesized into nanostructures or nanoparticles. Gener- ally, aluminum (Al), gold (Au), silver (Ag), copper (Cu), cobalt (Co), cadmium (Cd), lead (Pb), iron (Fe), and zinc (Zn) metals are used for nanostructure synthesis [50e52]. Inorganic metal nanoparticles possess unique properties, such as large surface areas, surface charge densities, pore sizes, and stability. These kinds of nanoparticles can be cylindrical or spherical in shape, crystalline or amorphous in structure, and typically less than 100 nm in size [53]. Metal oxide-based nano- structures are synthesized mainly because of their increased efficiency and reac- tivity. Metal oxide-based nanostructures are prepared in order to modify the physicochemical properties of their respective metal-based nanostructures. The most commonly used metal oxides for the synthesis of nanostructures that have been well characterized include zinc oxide and iron oxide nanostructures [54e56]. Iron oxide nanostructures have generated incredible interest in nanomedi- cine due to their many beneficial properties [57]. Specifically, it has been found that when iron oxide nanostructures are reduced to a size of 20 nm, they become superparamagnetic in the presence of a magnetic field; as a result, they have become very useful for applications, such as magnetic resonance imaging (MRI) and targeted drug delivery and release [58e60]. 6 Design and Applications of Theranostic Nanomedicines
- 20. 1.3 Design oftheranostic nanostructures as nanomedicines Nanotheranostic agents can be engineered in several ways. For instance, therapeutic agents (e.g., anticancer agents and photosensitizers) may be loaded into existing nano- particles that enable imaging, such as quantum dots, iron oxide nanostructures, and gold nanostructures. Another possibility is tagging of imaging contrast agents to the existing therapeutic nanostructures. In addition, encapsulating both imaging and ther- apeutic agents together in biocompatible nanostructures can be effective [61]. Finally, the engineering of unique nanostructures with intrinsic imaging and therapeutic prop- erties may yield beneficial results. The conceptual design of nanotheranostics has been broadly categorized in the literature [62e65]. Based on the classification by Ferrari [66], nanotheranostics can be dichotomized into three components, namely, biomed- ical payload, carriers, and surface modifiers (e.g., polyethylene glycol, dextran, poly- peptides), subject to their roles and their physical locations. 1.3.1 Therapeutic pay-loads 1.3.1.1 Therapeutics The therapy type most commonly delivered in nanostructures is cancer chemothera- peutics. Chemotherapy is the treatment of choice for most cancer cases, but drug toxicity, poor absorption to the tumor site, and multidrug resistance limit therapy [67]. Cancer cells differ from normal cells in that they usually grow faster and in an uncontrolled manner and show malignant behaviors like metastasis. The observed un- controlled and fast growth rates are empowered by fast DNA synthesis. Chemothera- peutic drugs act by interfering with the synthesis and function of DNA to halt cell divisions by specifically targeting the fast-dividing cells, ultimately leading to inhibi- tion of tumor growth and metastasis [68]. In order to vanquish the toxicity of chemo- therapeutics drugs, nanomedicine developments have emerged with theranostics nanostructure-based drug delivery systems. Nanostructure-based drug delivery sys- tems have great potential to lower cytotoxicity and enhance the therapeutic efficiency of anticancer drugs [69]. They can be engineered to target specific surface receptors on cancer cells, thus, facilitating targeted delivery [70]. In order to reduce the side effects of chemotherapeutic drugs on the normal healthy tissues, nanostructure-based drug de- livery treatments are required to realize higher efficacy with insignificant side effects. Nevertheless, theranostic nanostructure-based systems must be biodegradable and ideally display long systemic circulation half-life and targeted delivery into the specific tissue [71]. Nanostructure-based drug delivery systems can be tailor-made to selectively deliver drugs to the cancerous sites and reducing the chances of unspecific delivery to the non- cancerous tissues, thus, reducing the side effects of the chemotherapeutic agents [72,73]. Theranostic nanostructures as nanomedicines: benefits, costs, and future challenges 7
- 21. Hence, theranostic nanostructure-baseddrug delivery has the greatest potential for futur- istic applications for improved treatments of most diseases, including cancer. 1.3.1.2 Imaging There are several imaging modalities that can be integrated into nanotheranostics sys- tems. Herein, we discuss only the commonly used modalities such as optical imaging, magnetic resonance imaging (MRI), computed tomography (CT), positron emission tomography (PET), and single-photon emission computed tomography (SPECT). Among these modalities, CT and MRI have been widely studied modalities for image reconstruction due to low-dose CT and fast MRI repository. Nuclear imaging tech- niques, such as PET and SPECT, are very useful for nanotheranostics application, pre- dominantly due to high fidelity for detecting and characterize tumors before, during, and after therapy with chemotherapy and immunotherapy [25,74]. The optical imaging modality utilizes organic fluorescent dyes, such as fluorescein isothiocyanate (FITC) to monitor molecular events in biological systems [75]. Visible or ultraviolet (UV) light can be used to excite organic dyes. However, it does not penetrate deeply into tissues, limiting the application of organic dyes mainly to the bioimaging of cells. In addition, individual organic dyes are photo-bleachable and rather toxic. Consequently, methods have been developed whereby organic dyes are protectively encapsulated into nano- carriers, such as SiO2-matrices [76,77] or polymeric nanoparticles [78]. These have been developed to provide the desired photostability and decrease loss during delivery, resulting in lower imaging ability and increased toxicity. Matrix metalloproteinases (MMPs) on tumor cells can be useful targets for tumor imaging and treatment [79]. Typically, optical imaging probes are linked onto the ther- apeutic nanostructure via MMP-breakable peptide linkers, and the optical probes are “switched off” by a fluorescence resonance energy transfer (FRET) mechanism. The optical imaging probes are released from the nanostructure upon reaching target tumor cells, resulting in the fluorescence being “switched on” [79,80]. MRI is a noninvasive medical imaging tool to visualize detailed internal structures [81,82]. For MRI, atoms in the body are aligned under a powerful magnetic field. Radiofrequency fields change the alignment of the magnetization of atoms. This causes the nuclei to produce a rotating magnetic field detectable by the scanner, which can be recorded to construct an image of the body. Strong magnetic field gradients cause nuclei at different locations to rotate at different speeds, thus providing 3D spatial information. Compared with other medical imaging techniques, such as CT, MRI provides good contrast between the different soft tissues of the body, which makes it especially useful in imaging the brain, muscles, the heart, and cancers [83]. Another advantage of MRI is that it does not need to use ionizing radiation, damaging cell structure. PEGylated paramagnetic and fluorescent Gd diethylene triamine penta- acetic acid (DTPA)-bis(sterylamide) immunoliposomes are capable of detecting dese- lecting expression level [84]. E-selectin, an endothelial cell surface receptor, is imperative for pathophysiological and therapeutic responses, including avb3-integrins and the VEGF receptor. Liposome particles were designed to bind to E-selectin over- expressing HUVEC cells, and cell internalization was confirmed by boosting the T1- weighted MRI signal. 8 Design and Applications of Theranostic Nanomedicines
- 22. Regarding CT imaging,several studies have been conducted where chemothera- peutics were loaded into gold nanostructures for visualization by CT imaging. Kim et al. [85] reported a gold nanostructure for theranostic targeted molecular CT imaging and prostate cancer therapy. For targeting, the surface of gold nanostructure was deco- rated with a prostate-specific membrane antigen (PSMA) bound with RNA aptamer. In vitro experiments showed that the PSMA aptamer-conjugated gold nanostructure instigated at least a fourfold raise in CT intensity for a targeted LNCaP cell than that of a nontargeted PC3 cell. Furthermore, after loading the targeted gold nanostruc- ture with doxorubicin (DOX), drug release experiments showed that approximately 35% of DOX was released within 1 h. The particle potency against targeted LNCaP cells was significantly higher than against nontargeted PC3 cells. Another multifunc- tional theranostic gold nanostructure for targeted CT imaging and drug delivery was reported [86]. In this, dendrimer-entrapped gold nanostructure was covalently linked with a-tocopheryl succinate (a-TOS), which possesses intrinsic anticancer activity (a-TOS can induce apoptosis of various cancer cells), inhibit the cell cycle, and inter- rupt signaling pathways of tumor growth but not affecting the proliferation of normal cells [2]. PET and SPECT are both imaging techniques that utilize g-rays emanating from the decay of radioactive sources inside the body. Consequently, these modalities require the administration of radio-nuclides to generate the signal for image construction [87]. These imaging modalities offer several advantages: higher sensitivity, noninva- siveness, little background noise, and the generation of three-dimensional images in a real-time manner. PET is more sensitive than SPECT and is often associated with other techniques like CT to obtain anatomical contrast [88]. Nanostructures can provide an excellent platform for the attachment of radioisotopes for nanotheranostics applica- tions (i.e., early diagnosis of diseases and combining in vivo imaging and drug deliv- ery. Furthermore, using radiolabeled nanoparticles enhances the accumulation of the radioisotopes in the tumor by EPR effect, reducing the number of these agents in nontarget tissues, generating an even higher sensitivity to the techniques [87]. 1.3.2 Nanocarriers 1.3.2.1 Polymeric nanoparticles and micelles Polymers are among the most easy-handled and economical carriers due to their important characteristics, such as biocompatibility, biodegradability, and stability against degradation [1]. Both synthetic and natural macromolecules have been utilized as nanotheranostics. However, they should be first modified to possess imaging ability and therapeutic activity [89]. Sachdev and Matai [90] developed chitosan-based hydrogel loaded with highly fluorescent carbon dots and anticancer drug, 5- fluorouracil. The cross-sectional view demonstrated an irregular morphology with highly porous and interconnected networks, indicating a typical of hydrogels. Carbon dots were found as confined to be visualized by field emission-scanning electron mi- croscopy (FE-SEM) (Fig. 1.1a). The occurrences of carbon dots in matrices of hydro- gels could be clearly distinguished by transmission electron microscope (TEM) Theranostic nanostructures as nanomedicines: benefits, costs, and future challenges 9
- 23. micrographs, wherein numerousdark tiny domains of carbon dots produced a clear contrast with the comparatively gray hydrogel matrix (Fig. 1.1b). High-resolution TEM micrographs further demonstrated uniform distribution of carbon dots within the hydrogel matrix (Fig. 1.1c). It was found out that the system was able to show cellular uptake as well as therapeutic effects. In addition, in vitro studies exhibited apoptosis in A549 cells. Manifestation of apoptosis in chitosan-based hydrogel loaded with highly fluorescent carbon dots and 5-fluorouracil treated A549 cells was evi- denced by FE-SEM images (Fig. 1.2). Treated A549 cells underwent shape change and drastic shrinkage in comparison to that of untreated A549 cells. To sum up, the green fluorescence of carbon dots could be used to detect apoptosis instigated by 5- fluorouracil, eliminating the need for multiplex dyes. Other polymers have also been employed as nanotheranostics. 1.3.2.2 Lipid nanovesicles Liposomes are relatively stable, consist of structured biocompatible and biodegradable lipid carriers; some liposomes have been approved by FDA [91]. In most cases, lipo- somes are functionalized or coated with active molecules such as PEG, vitamins that Figure 1.1 (a) FE-SEM (b) TEM and (c) High resolution TEM image of freeze-dried chitosan- based hydrogel loaded with highly fluorescent carbon dots and 5-fluorouracil [90]. With permission, Copyright © 2016 Elsevier B.V. Figure 1.2 FE-SEM micrographs of (a) untreated and (b) chitosan-based hydrogel loaded with highly fluorescent carbon dots and 5-fluorouracil treated A549 cells after 48 h incubation [90]. With permission, Copyright © 2016 Elsevier B.V. 10 Design and Applications of Theranostic Nanomedicines
- 24. can induce theirbiocompatibility. For example, vitamin E TPGS-coated liposomes are widely prepared [92]. In further, PEG-coated and folate-PEG-coated long-circulating and pH-sensitive liposomes loaded with 159 Gd and poly-L-lysine (159 Gd-SpHL and 159 Gd-FTSpHL, respectively) were studied as cancer nanotheranostics [93]. The pre- pared liposomes provide increased animal survival and high tumor uptake. Scinti- graphic photographs obtained at 1, 4, 6, and 8 h after intravenous (i.v.) administration of PEG-coated and folate-PEG-coated long-circulating pH-sensitive li- posomes loaded with 159 Gd and poly-L-lysine (159 Gd-SpHL and 159 Gd-FTSpHL, respectively) are shown in Fig. 1.3. The advanced theranostic liposomes are conju- gated with molecular biomarkers for targeting effect. To overcome opsonization by the immune system and fast elimination from blood circulation, stealth liposomes, i.e., PEG-coated liposomes, were formulated with stability and a longer half-life in blood [94]. 1.3.2.3 Dendrimers Dendrimers are synthetic nanomedicine that comprises a highly branched spherical polymer. These are used in nanotheranostics are typically less than 100 nm [95]. The higher generation dendrimers resemble the spherical shape, having a number of cavities and branches capable of encapsulating both therapeutic agents and diagnostic agents for nanotheranostics applications. The fifth generation of dendrimers displays more hydrophobicity. It is generally preferred owing to enhanced encapsulation Figure 1.3 Scintigraphic photographs obtained at 1, 4, 6, and 8 h after I.V. administration of PEG-coated and folate-PEG-coated long-circulating and pH-sensitive liposomes loaded with 159 Gd and poly-L-lysine (159 Gd-SpHL and 159 Gd-FTSpHL, respectively); Arrows indicate tumor site [93]. With permission, Copyright © 2015 Elsevier B.V. Theranostic nanostructures as nanomedicines: benefits, costs, and future challenges 11
- 25. efficiency and stabilityof guest molecules (i.e., drug and diagnostic agent) in a den- dritic matrix [96,97]. 1.3.2.4 Protein-based nanostructures Proteins, mostly therapeutic proteins, have been developed to treat various diseases, including cancer, infections, and genetic disorders [98]. Recently, protein-based bio- materials with eminent biocompatibility have shown widespread potential applications in nanotheranostics. Fluorescent proteins and proteins labeled with fluorescent dyes can be simply traced under in vivo fluorescence imaging. Notably, in vivo imaging us- ing fluorescent antibodies has been used for theranostic applications (i.e., imaging, diagnosis, and predicting therapeutic responses) [98]. 1.3.2.5 Metallic nanostructures Several metallic nanostructures have extensively been investigated for nanotheranos- tics applications [99,100]. Among metallic nanostructures that have been studied, gold, and iron have shown fascinated results. Gold nanostructures based on gold cores are prepared with a small core size from 1.5 to 10 nm, providing a large area for effi- cient drug and ligand conjugations [101]. The chemical treatment of hydrogen tetra- chloroaurate generally manufactures gold nanostructures. Gold nanostructures can be conjugated with drug and targeting ligand as advanced nanotheranostics that spe- cifically recognizes the target receptor for active targeting [102]. Drug loading can be achieved by either electrostatic interaction or covalent chemical conjugation, depending on the nature of the parent drug. The inherent features of gold nanostruc- tures include diagnostic property, tunable core size, low toxicity, large surface to vol- ume ratio, surface plasmon absorption, light-scattering properties, and ease of synthesis [102,103]. Metallic magnetic nanostructures (MNS) have especially attracted considerable attention from scientists for addressing cancer nanotheranostics [104,105]. The diag- nostics potential of MNS arises from their role in enhancing the contrast in MRI. The therapeutic prospects of MNS stem from thermal activation under externally applied radio frequency (RF) field and localized release of therapeutic cargo [104]. Fe3O4 MNS are extensively used in nanotheranostics because of their biocompatibility and ease of synthesis. The magnetic moment (which influences MRI fidelity) of super- paramagnetic Fe3O4 MNS is dependent on the size of smaller particles producing lower magnetic moments [102]. MRI-based immune cell tracing using MNS has been applied to several biological studies, such as tumor targeting of cytotoxic T cells and natural killer cells [104]. 1.3.2.6 Ceramic nanostructures Ceramic nanostructures or nanoceramics are emerging as a novel platform for nano theranostics applications mainly due to their small size (50 nm) and physicochemical properties. They include particles made from silica, iron oxide, or aluminum [106]. Mesoporous silica nanoparticles (MSNs) are promising functional nanostructures for 12 Design and Applications of Theranostic Nanomedicines
- 26. various nanotheranostics applications(such as bioimaging, drug/gene delivery, and cancer therapy). This is due to their low density, low toxicity, high biocompatibility, large specific surface areas, and excellent thermal and mechanical stability. Aluminum oxide (Al2O3) ceramic nanostructures have also been used for nanotheranostics appli- cations; these ceramic nanostructures are not vulnerable to swelling or changes in porosity with pH [107]. Furthermore, ceramic nanostructures can protect different bio- macromolecules, such as enzymes, against denaturation induced by the external pH and temperature [108]. 1.3.2.7 Nanocomposites Nanocomposites represent a current trend in developing novel nanostructured bioma- terials [109]. They comprise a combination of two or more nanostructures containing different compositions or structures [110,111]. Shen et al. [112] synthesized a multi- functional nanocomposite of poly(D,L-lactic-co-glycolic acid) (PLGA)-based lumines- cent/magnetic hybrid nanocomposite modified with polyethyleneimine premodified with polyethylene glycol-folic acid (PEI-PEG-FA) segments for codelivery of DOX and VEGF small hairpin RNA (shRNA) (LDM-PLGA/PPF/VEGF shRNA). The PEG-conjugated copolymer was used to prevent aggregation particles and achieve a prolonged circulation time, in vivo. PLGA was chosen due to its biocompatibility and biodegradability. The drug release behavior, folate receptor-mediated cell uptake, cytotoxicity, escape from endosomes/lysosomes, gene expression, MR and fluores- cence imaging, and antitumor effects in an animal model of the developed nanocom- posites were investigated. The nanocomposites revealed a fascinated results and could be used as a dual-modality imaging nanoprobe for enhanced T2-weighted MR imaging and tumor fluorescence imaging, both in vitro and in vivo [112]. In a research, Wu et al. [113] developed DOX-loaded mesoporous magnetic nanocomposites (CS/ Fe3O4@mSiO2-DOX), where chitosan was employed as blocking agent to avoid pre- mature release of DOX (Fig. 1.4). The release of DOX from these developed DOX- loaded nanocomposites was revealed for pH responsive behavior and 86.1% DOX was released at pH 4 within 48 h (Fig. 1.5). 1.3.2.8 Nanoconjugates Nanotheranostics, particularly nanophototheranostics (which employ photosensi- tizers), can be considered for treating metastatic and drug-resistant cancers as these can combine targeting, imaging, and nanoconjugated therapeutic agents [114]. Recently, photosensitizers loaded on nanoscaffolds are widely being used as theranos- tic nanoconjugates for their capability to serve as both therapeutic and imaging mod- ules through a single moiety. Near-IR absorbing photosensitizers can take part in performing both detection and treatment of various diseases. An advantage of using nanophotosensitizers as theranostic agents is that they tend to possess lower toxicity and provide sophisticated treatment modules, thus minimizing lengthy recovery time for patients [115]. Pectin-conjugated graphene oxide nanoconjugate was devel- oped to deliver anticancer agent-paclitaxel [116]. In vitro cytotoxic studies including Theranostic nanostructures as nanomedicines: benefits, costs, and future challenges 13
- 27. MTT assay werecarried out using L929 and MCF-7 cell lines. Popat et al. [117] syn- thesized curcumin-cyclodextrin-encapsulated chitosan nanoconjugates with improved solubility of curcumin and augmented the cellular uptake. Curcumin-cyclodextrin was synthesized by a novel spray drying method. The scanning electron microscopy (SEM) indicated the formation of spray dried hollow microspheres (Fig. 1.6). 1.4 Applications of theranostic nanostructures as nanomedicines Nanotheranostics has emerged as a fascinated platform for prompt detection and treat- ment of initially untreatable diseases under conventional therapeutic regimens [118]. Diseases, such as congenital genetic malformations and cancers, can now be easily diagnosed and treated by employing various imaging techniques adopting genomics, proteomics, and nanostructures to detect several biomarkers based on understanding disease pathways [119]. The biomarkers have a great deal of promise as tools for can- cer detection, diagnosis, patient prognosis, and therapy. Understanding genomics for a Figure 1.4 Diagram of the preparation and controlled release process of CS/Fe3O4@mSiO2- DOX [113]. With permission, Copyright © 2016 Elsevier B.V. 14 Design and Applications of Theranostic Nanomedicines
- 28. certain disease isthe basis for gene therapy. Recently, a biocompatible poly(D,L-lac- tide-co-glycolide) (PLG) nanostructures containing an imaging probe and therapeutic gene were prepared, followed by modification with rabies virus glycoprotein (RVG) peptide for neuroblastoma-targeting delivery [120]. RVG-modified nanostructures were effective in specifically targeting neuroblastoma, both in vitro and in vivo. RVG-modified nanoparticles loaded with a fluorescent probe are helpful to detect the tumor site in a neuroblastoma-bearing mouse model, and those encapsulating a therapeutic gene cocktail (siMyc, siBcl-2, and siVEGF) significantly suppressed tumor growth in the mouse model. This approach for targeted delivery could be useful in developing multimodality systems for nanotheranostics approaches [120]. Shao et al. [121] fabricated an HSV-TK/GCV suicide gene system and near- infrared quantum dots for liver cancer treatment tumor imaging. In their study, a folate-modified theranostic liposome (FL/QD-TK) was developed, composed of an HSV-TK suicide gene covalently coupling with near-IR fluorescent CdSeTe/ZnS core/shell quantum dots. The FL/QD-TK exhibited highly specific tumor imaging and strong inhibition of the folate receptor-overexpressed Bel-7402 mouse xenografts without systematic toxicity. This study could shed light on gene delivery and targeted cancer therapy. Figure 1.5 In vitro cumulative release of DOX from (a) CS/Fe3O4@mSiO2-DOX, (b) CS/ Fe3O4@mSiO2-DOX at 37C in PBS buffer at pH 7.5, 5.8, and 4.0, and (c) First-order model and (d) Higuchi model of DOX released from CS/Fe3O4@mSiO2-DOX. Results are expressed as the mean SD of three independent experiments [113]. With permission, Copyright © 2016 Elsevier B.V. Theranostic nanostructures as nanomedicines: benefits, costs, and future challenges 15
- 29. Surgeons have recentlyapplied advanced nanotheranostics for enhancing surgical performances and clinical outcomes through medical robotics coupled with miniature imaging probes. Medical robots have been receiving growing attention due to techno- logical advances. They have significant potential to reduce the invasiveness and improve the accessibility of medical devices into unprecedented small spaces inside the human body. 3D fabrication technologies have enabled medical robotic fabrication at the single-cell scale for empowering high-resolution visual imaging and in vivo manipulation capabilities [122]. Injectable ocular nanorobots allow the gastric ulcer imaging and performance of vitreoretinal microsurgery at previously inaccessible ocular sites. Many invasive excision and incision based diagnostic and prostrate sur- gery can be performed minimally or almost noninvasively due to recent advancements in medical robotics [123]. Such medical robotics systems could be used for local tar- geted delivery of imaging contrast agents, drugs, genes, and mRNA, minimally inva- sive surgery, and cell micromanipulation in the near future [122]. 1.5 Benefits and costs of theranostic nanostructures as nanomedicines Compared with the conventional way of delivering therapeutic or imaging agents sepa- rately, nanotheranostics encompasses simultaneously delivering imaging and thera- peutic agents to specific sites or organs. Thus, nanotheranostics enables the detection and treatment of a disease in a single procedure. When therapeutic and im- aging agents are formulated in a fixed-dose combination, they are usually assumed to Figure 1.6 Schematic representations of (a) synthesis of highly soluble curcumin-cyclodextrin complex by a novel spray drying method. The SEM image represents hollow microspheres after spray drying and inset shows a water solution of curcumin-cyclodextrin; (b) synthesis method of curcumin-cyclodextrin-encapsulated chitosan nanoconjugates [117]. 16 Design and Applications of Theranostic Nanomedicines
- 30. have similar biodistributionand tumor localization in the body. Consequently, nano- theranostics agents are expected to inform us about the localization of the drug and pathological prognosis on a real-time basis. In situ imaging of theranostic pharmacokinetics can provide important insight into heterogeneities between tumors and patients. This will benefit physicians for making informed decisions about timing, dosage adjustments, choice of drug, and treatment strategies. This constitutes the concept of “personalized medicine,” which can lead to improved efficacy, lower off-target toxicity, and an overall enhancement of quality of life and patient treatment outcomes. 1.6 Challenges of theranostic nanostructures as nanomedicines Although nanotheranostics is still at its infancy stage in the field of nanomedicine, the trend toward combining diagnostic and therapeutic functions of theranostic nanostruc- tures in a single platform has been recently gaining momentum, resulting in signifi- cantly improved and personalized disease management. However, to realize the clinical potential of nanotheranostics, researchers should address several challenges. These challenges may include selecting the ideal nanoplatform, improving ligand conjugation efficiency, and developing an ideal synthetic technique with fewer manufacturing steps and high reproducibility. Another issue is the trade-off between the desired concentration of therapeutic and imaging agents incorporated in the nano- theranostics platform. That is, how much imaging or therapeutic efficacy is one willing to sacrifice in order to achieve the desired advantage of having dual functionality. For instance, while long systemic circulation times are generally preferred for therapeutic nanostructures, this is not ideal for imaging. 1.7 Conclusion We have recently witnessed a very fast pace for the growing trend of nanotheranostics in nanomedicines for disease (especially cancer) imaging and therapy. The current sta- tus, challenges, and the prospect of tumor actively targeted nanostructures were dis- cussed in this chapter. The development of nanotheranostics that is targetable, safe, and efficacious will continue to focus on futuristic applications. The philosophy is to formulate nanotheranostics that will be holding a greater potential for clinical applications. References [1] Siafaka PI, € Ust€ unda g Okur N, Karavas E, Bikiaris DN. Surface modified multifunctional and stimuli responsive nanoparticles for drug targeting: current status and uses. Int J Mol Sci 2016;17(9):1440. Theranostic nanostructures as nanomedicines: benefits, costs, and future challenges 17
- 31. [2] Wande DP,Cui Q, Chen S, Xu C, Xiong H, Yao J. Rediscovering tocophersolan: a re- naissance for nano-based drug delivery and nanotheranostic applications. Curr Drug Targets 2021;22(8):856e69. [3] Qi B, Crawford AJ, Wojtynek NE, Talmon GA, Hollingsworth MA, Ly QP, Mohs AM. Tuned near infrared fluorescent hyaluronic acid conjugates for delivery to pancreatic cancer for intraoperative imaging. Theranostics 2020;10(8):3413e29. [4] Ferber S, Baabur-Cohen H, Blau R, Epshtein Y, Kisin-Finfer E, Redy O, Shabat D, Satchi-Fainaro R. Polymeric nanotheranostics for real-time non-invasive optical imaging of breast cancer progression and drug release. Cancer Lett 2014;352(1):81e9. [5] Das SS, Alkahtani S, Bharadwaj P, Ansari MT, ALKahtani MDF, Pang Z, Hasnain MS, Nayak AK, Aminabhavi TM. Molecular insights and novel approaches for targeting tu- mor metastasis. Int J Pharm 2020;585:119556. [6] Luque-Michel E, Imbuluzqueta E, Sebasti an V, Blanco-Prieto MJ. Clinical advances of nanocarrier-based cancer therapy and diagnostics. Expet Opin Drug Deliv 2017;14(1): 75e92. [7] Pelaz B, Alexiou C, Alvarez-Puebla RA, Alves F, Andrews AM, Ashraf S, Balogh LP, Ballerini L, Bestetti A, Brendel C, Bosi S, Carril M, Chan WC, Chen C, Chen X, Chen X, Cheng Z, Cui D, Du J, Dullin C, Escudero A, Feliu N, Gao M, George M, Gogotsi Y, Gr€ unweller A, Gu Z, Halas NJ, Hampp N, Hartmann RK, Hersam MC, Hunziker P, Jian J, Jiang X, Jungebluth P, Kadhiresan P, Kataoka K, Khademhosseini A, Kope cek J, Kotov NA, Krug HF, Lee DS, Lehr CM, Leong KW, Liang XJ, Ling Lim M, Liz- Marz an LM, Ma X, Macchiarini P, Meng H, Möhwald H, Mulvaney P, Nel AE, Nie S, Nordlander P, Okano T, Oliveira J, Park TH, Penner RM, Prato M, Puntes V, Rotello VM, Samarakoon A, Schaak RE, Shen Y, Sjöqvist S, Skirtach AG, Soliman MG, Stevens MM, Sung HW, Tang BZ, Tietze R, Udugama BN, VanEpps JS, Weil T, Weiss PS, Willner I, Wu Y, Yang L, Yue Z, Zhang Q, Zhang Q, Zhang XE, Zhao Y, Zhou X, Parak WJ. Diverse applications of nanomedicine. ACS Nano 2017;11(3): 2313e81. [8] Cole AJ, Yang VC, David AE. Cancer theranostics: the rise of targeted magnetic nano- particles. Trends Biotechnol 2011;29(7):323e32. [9] Kelkar SS, Reineke TM. Theranostics: combining imaging and therapy. Bioconjugate Chem 2011;22(10):1879e903. [10] Thakkar S, Sharma D, Kalia K, Tekade RK. Tumor microenvironment targeted nano- therapeutics for cancer therapy and diagnosis: a review. Acta Biomater 2020;101:43e68. [11] Yang F, Zhao Z, Sun B, Chen Q, Sun J, He Z, Luo C. Nanotherapeutics for antimetastatic treatment. Trends Cancer 2020;6(8):645e59. [12] Shao L, Li Q, Zhao C, Lu J, Li X, Chen L, Deng X, Ge G, Wu Y. Auto-fluorescent polymer nanotheranostics for self-monitoring of cancer therapy via triple-collaborative strategy. Biomaterials 2019;194:105e16. [13] Panigrahi BK, Nayak AK. Carbon nanotubes: an emerging drug delivery carrier in cancer therapeutics. Curr Drug Deliv 2020;17:558e76. [14] Costa PM, Wang JT, Morfin JF, Khanum T, To W, Sosabowski J, T oth E, Al-Jamal KT. Functionalised carbon nanotubes enhance brain delivery of amyloid-targeting pittsburgh compound B (PiB)-derived ligands. Nanotheranostics 2018;2(2):168e83. [15] Wang JT, Hodgins NO, Al-Jamal WT, Maher J, Sosabowski JK, Al-Jamal KT. Organ biodistribution of radiolabelled gd t cells following liposomal alendronate administration in different mouse tumour models. Nanotheranostics 2020;4(2):71e82. [16] Bhattacharjee A, Das PJ, Dey S, Nayak AK, Roy PK, Chakrabarti S, Marbaniang D, Das SK, Ray S, Chattopadhyay P, Mazumder B. Development and optimization of 18 Design and Applications of Theranostic Nanomedicines
- 32. besifloxacin hydrochloride loadedliposomal gel prepared by thin film hydration method using 32 full factorial design. Colloids Surf A Physicochem Eng Asp 2020;585:124071. [17] Medalsy I, Dgany O, Sowwan M, Cohen H, Yukashevska A, Wolf SG, Wolf A, Koster A, Almog O, Marton I, Pouny Y, Altman A, Shoseyov O, Porath D. SP1 protein-based nanostructures and arrays. Nano Lett 2008;8(2):473e7. [18] Fu F, Wu Y, Zhu J, Wen S, Shen M, Shi X. Multifunctional lactobionic acid-modified dendrimers for targeted drug delivery to liver cancer cells: investigating the role played by PEG spacer. ACS Appl Mater Interfaces 2014;6(18):16416e25. [19] Jang D, Meza LR, Greer F, Greer JR. Fabrication and deformation of three-dimensional hollow ceramic nanostructures. Nat Mater 2013;12(10):893e8. [20] Mardhian DF, Vrynas A, Storm G, Bansal R, Prakash J. FGF2 engineered SPIONs attenuate tumor stroma and potentiate the effect of chemotherapy in 3D heterospheroidal model of pancreatic tumor. Nanotheranostics 2020;4(1):26e39. [21] Sung SY, Su YL, Cheng W, Hu PF, Chiang CS, Chen WT, Hu SH. Graphene quantum dots-mediated theranostic penetrative delivery of drug and photolytics in deep tumors by targeted biomimetic nanosponges. Nano Lett 2019;19(1):69e81. [22] National Research Council. Small wonders, endless frontiers: a review of the national nanotechnology initiative. Washington, DC: The National Academies Press; 2002. https://doi.org/10.17226/10395. Retrieved from. [23] Bayda S, Adeel M, Tuccinardi T, Cordani M, Rizzolio F. The history of nanoscience and nanotechnology: from chemical-physical applications to nanomedicine. Molecules 2019; 25(1):112. [24] Mansoori GA, Soelaiman TA. Nanotechnologydan introduction for the standards community. J ASTM Int (JAI) 2005;2:1e22. [25] Siafaka PI, Okur N€ U, Karantas ID, Okur ME, G€ undo gdu EA. Current update on nano- platforms as therapeutic and diagnostic tools: a review for the materials used as nano- theranostics and imaging modalities. Asian J Pharm Sci 2021;16(1):24e46. [26] Hasnain MS, Nayak AK. Carbon nanotubes as quantum dots for therapeutic purpose. In: Hasnain MS, Nayak AK, editors. Carbon nanotubes for targeted drug delivery. Singapore: Springer; 2019. p. 59e64. [27] Jeevanandam J, Barhoum A, Chan YS, Dufresne A, Danquah MK. Review on nano- particles and nanostructured materials: history, sources, toxicity and regulations. Beilstein J Nanotechnol 2018;9:1050e74. [28] Anu Mary Ealia S, Saravanakumar MP. A review on the classification, characterisation, synthesis of nanoparticles and their application. IOP Conf Ser Mater Sci Eng 2017;263: 032019. [29] Nasrollahzadeh M, Issaabadi Z, Sajjadi M, Sajadi SM, Atarod M. Chapter 2dtypes of nanostructures. In: Nasrollahzadeh M, Sajadi SM, Sajjadi M, Issaabadi Z, Atarod T, editors. An introduction to green nanotechnology. vol 28. USA: Elsevier; 2019. p. 29e80. [30] Ansari AA, Hasan TN, Syed NA, Labis JP, Parchur AK, Shafi G, Alshatwi AA. In-vitro cyto-toxicity, geno-toxicity, and bio-imaging evaluation of one-pot synthesized lumi- nescent functionalized mesoporous SiO2@Eu(OH)3 core-shell microspheres. Nano- medicine 2013;9(8):1328e35. [31] Hasnain MS, Nayak AK. Background: carbon Nanotubes for targeted drug delivery. In: Hasnain MS, Nayak AK, editors. Carbon nanotubes for targeted drug delivery. Singapore: Springer; 2019. p. 1e9. [32] Hasnain MS, Nayak AK. Classification of carbon nanotubes. In: Hasnain MS, Nayak AK, editors. Carbon nanotubes for targeted drug delivery. Singapore: Springer; 2019. p. 11e5. Theranostic nanostructures as nanomedicines: benefits, costs, and future challenges 19
- 33. [33] Kostarelos K,Bianco A, Prato M. Promises, facts and challenges for carbon nanotubes in imaging and therapeutics. Nat Nanotechnol 2009;4(10):627e33. [34] Hasnain MS, Nayak AK. Characterization of carbon nanotubes. In: Hasnain MS, Nayak AK, editors. Carbon nanotubes for targeted drug delivery. Singapore: Springer; 2019. p. 29e31. [35] Kang B, Yu D, Dai Y, Chang S, Chen D, Ding Y. Cancer-cell targeting and photoacoustic therapy using carbon nanotubes as “bomb” agents. Small 2009;5(11):1292e301. [36] Zavaleta C, de la Zerda A, Liu Z, Keren S, Cheng Z, Schipper M, Chen X, Dai H, Gambhir SS. Noninvasive Raman spectroscopy in living mice for evaluation of tumor targeting with carbon nanotubes. Nano Lett 2008;8(9):2800e5. [37] Hasnain MS, Nayak AK. Carbon nanotubes in controlled drug delivery. In: Hasnain MS, Nayak AK, editors. Carbon nanotubes for targeted drug delivery. Singapore: Springer; 2019. p. 51e4. [38] Hasnain MS, Nayak AK. Toxicity consideration of carbon nanotubes. In: Hasnain MS, Nayak AK, editors. Carbon nanotubes for targeted drug delivery. Singapore: Springer; 2019. p. 89e101. [39] Schipper ML, Nakayama-Ratchford N, Davis CR, Kam NW, Chu P, Liu Z, Sun X, Dai H, Gambhir SS. A pilot toxicology study of single-walled carbon nanotubes in a small sample of mice. Nat Nanotechnol 2008;3(4):216e21. [40] Kumar V, Kumar A, Lee DJ, Park SS. Estimation of number of graphene layers using different methods: a focused review. Materials 2021;14(16):4590. [41] Bhuyan MSA, Uddin MN, Islam MM, et al. Synthesis of graphene. Int Nano Lett 2016;6: 65e83. [42] Kumar M, Raza K. C60-fullerenes as drug delivery carriers for anticancer agents: promises and hurdles. Pharm Nanotechnol 2017;5(3):169e79. [43] Thakral S, Mehta RM. Fullerenes: an introduction and overview of their biological properties. Indian J Pharmaceut Sci 2006;68:13e9. [44] Patra JK, Das G, Fraceto LF, Campos EVR, Rodriguez-Torres MDP, Acosta-Torres LS, Diaz-Torres LA, Grillo R, Swamy MK, Sharma S, Habtemariam S, Shin HS. Nano based drug delivery systems: recent developments and future prospects. J Nanobiotechnol 2018; 16(1):71. [45] Hussein Kamareddine M, Ghosn Y, Tawk A, Elia C, Alam W, Makdessi J, Farhat S. Organic nanoparticles as drug delivery systems and their potential role in the treatment of chronic myeloid leukemia. Technol Cancer Res Treat 2019;18. 1533033819879902. [46] Abbasi E, Aval SF, Akbarzadeh A, Milani M, Nasrabadi HT, Joo SW, Hanifehpour Y, Nejati-Koshki K, Pashaei-Asl R. Dendrimers: synthesis, applications, and properties. Nanoscale Res Lett 2014;9(1):247. [47] Ghosh B, Biswas S. Polymeric micelles in cancer therapy: state of the art. J Contr Release 2021;332:127e47. [48] Ghezzi M, Pescina S, Padula C, Santi P, Del Favero E, Cant u L, Nicoli S. Polymeric micelles in drug delivery: an insight of the techniques for their characterization and assessment in biorelevant conditions. J Contr Release 2021;332:312e36. [49] Khafaji M, Zamani M, Golizadeh M, Bavi O. Inorganic nanomaterials for chemo/pho- tothermal therapy: a promising horizon on effective cancer treatment. Biophys Rev 2019; 11(3):335e52. [50] Fan Z, Huang X, Tan C, Zhang H. Thin metal nanostructures: synthesis, properties and applications. Chem Sci 2015;6(1):95e111. [51] Huo D, Kim MJ, Lyu Z, Shi Y, Wiley BJ, Xia Y. One-dimensional metal nanostructures: from colloidal syntheses to applications. Chem Rev 2019;119(15):8972e9073. 20 Design and Applications of Theranostic Nanomedicines
- 34. [52] Ye J,Helmi S, Teske J, Seidel R. Fabrication of metal nanostructures with programmable length and patterns using a modular DNA platform. Nano Lett 2019;19(4):2707e14. [53] Yi Z, Yi Y, Luo J, Ye X, Wu P, Ji X, Jiang X, Yi Y, Tang Y. Experimental and simulative study on surface enhanced Raman scattering of rhodamine 6G adsorbed on big bulk- nanocrystalline metal substrates. RSC Adv 2015;5:1718e29. [54] Fan Z, Lu JG. Zinc oxide nanostructures: synthesis and properties. J Nanosci Nano- technol 2005;5(10):1561e73. [55] Hu SB, Li L, Luo MY, Yun YF, Chang CT. Aqueous norfloxacin sonocatalytic degra- dation with multilayer flower-like ZnO in the presence of peroxydisulfate. Ultrason Sonochem September 2017;38:446e54. [56] Wang ZL. Zinc oxide nanostructures: growth, properties and applications. J Phys Con- dens Matter 2004;16:829e58. [57] Laurent S, Forge D, Port M, Roch A, Robic C, Vander Elst L, Muller RN. Magnetic iron oxide nanoparticles: synthesis, stabilization, vectorization, physicochemical character- izations, and biological applications. Chem Rev 2008;108(6):2064e110. [58] Yu MK, Jeong YY, Park J, Park S, Kim JW, Min JJ, Kim K, Jon S. Drug-loaded superparamagnetic iron oxide nanoparticles for combined cancer imaging and therapy in vivo. Angew Chem Int Ed Engl 2008;47(29):5362e5. [59] Dilnawaz F, Singh A, Mohanty C, Sahoo SK. Dual drug loaded superparamagnetic iron oxide nanoparticles for targeted cancer therapy. Biomaterials 2010;31(13):3694e706. [60] Jun YW, Lee JH, Cheon J. Chemical design of nanoparticle probes for high-performance magnetic resonance imaging. Angew Chem Int Ed Engl 2008;47(28):5122e35. [61] Chen F, Ehlerding EB, Cai W. Theranostic nanoparticles. J Nucl Med 2014;55(12): 1919e22. [62] Labhasetwar V, Zborowski M, Abramson AR, Basilion JP. Nanoparticles for imaging, diagnosis, and therapeutics. Mol Pharm 2009;6(5):1261e2. [63] Lee DE, Koo H, Sun IC, Ryu JH, Kim K, Kwon IC. Multifunctional nanoparticles for multimodal imaging and theragnosis. Chem Soc Rev 2012;41(7):2656e72. [64] Minelli C, Lowe SB, Stevens MM. Engineering nanocomposite materials for cancer therapy. Small 2010;6(21):2336e57. [65] Muthu MS, Leong DT, Mei L, Feng SS. Nanotheranosticsdapplication and further development of nanomedicine strategies for advanced theranostics. Theranostics 2014; 4(6):660e77. [66] Ferrari M. Cancer nanotechnology: opportunities and challenges. Nat Rev Cancer 2005; 5(3):161e71. [67] Depalo N, Iacobazzi RM, Valente G, Arduino I, Villa S, Canepa F, Laquintana V, Fanizza E, Striccoli M, Cutrignelli A, Lopedota A, Porcelli L, Azzariti A, Franco M, Curri ML, Denora N. Sorafenib delivery nanoplatform based on superparamagnetic iron oxide nanoparticles magnetically targets hepatocellular carcinoma. Nano Res 2017;10: 2431e48. [68] Cheung-Ong K, Giaever G, Nislow C. DNA-damaging agents in cancer chemotherapy: serendipity and chemical biology. Chem Biol 2013;20(5):648e59. [69] Zhang NN, Yu RS, Xu M, Cheng XY, Chen CM, Xu XL, Lu CY, Lu KJ, Chen MJ, Zhu ML, Weng QY, Hui JG, Zhang Q, Du YZ, Ji JS. Visual targeted therapy of hepatic cancer using homing peptide modified calcium phosphate nanoparticles loading doxo- rubicin guided by T1 weighted MRI. Nanomedicine 2018;14(7):2167e78. [70] Mishra N, Yadav NP, Rai VK, Sinha P, Yadav KS, Jain S, Arora S. Efficient hepatic delivery of drugs: novel strategies and their significance. BioMed Res Int 2013;2013: 382184. Theranostic nanostructures as nanomedicines: benefits, costs, and future challenges 21
- 35. [71] Lata S,Sharma G, Joshi M, Kanwar P, Mishra T. Role of nanotechnology in drug de- livery. Int J Nanotechnol Nanosci 2017;7(5):1e29. [72] Amreddy N, Babu A, Muralidharan R, Panneerselvam J, Srivastava A, Ahmed R, Mehta M, Munshi A, Ramesh R. Recent advances in nanoparticle-based cancer drug and gene delivery. Adv Cancer Res 2018;137:115e70. [73] Ashfaq UA, Riaz M, Yasmeen E, Yousaf MZ. Recent advances in nanoparticle-based targeted drug-delivery systems against cancer and role of tumor microenvironment. Crit Rev Ther Drug Carrier Syst 2017;34(4):317e53. [74] Ng TSC, Garlin MA, Weissleder R, Miller MA. Improving nanotherapy delivery and action through image-guided systems pharmacology. Theranostics 2020;10(3):968e97. [75] Lim EK, Kim T, Paik S, Haam S, Huh YM, Lee K. Nanomaterials for theranostics: recent advances and future challenges. Chem Rev 2015;115(1):327e94. [76] Qian HS, Guo HC, Ho PC, Mahendran R, Zhang Y. Mesoporous-silica-coated up- conversion fluorescent nanoparticles for photodynamic therapy. Small 2009;5(20): 2285e90. [77] Wu SH, Lin YS, Hung Y, Chou YH, Hsu YH, Chang C, Mou CY. Multifunctional mesoporous silica nanoparticles for intracellular labeling and animal magnetic resonance imaging studies. Chembiochem January 4, 2008;9(1):53e7. [78] Talanov VS, Regino CA, Kobayashi H, Bernardo M, Choyke PL, Brechbiel MW. Dendrimer-based nanoprobe for dual modality magnetic resonance and fluorescence imaging. Nano Lett 2006;6(7):1459e63. [79] Kessenbrock K, Plaks V, Werb Z. Matrix metalloproteinases: regulators of the tumor microenvironment. Cell 2010;141(1):52e67. [80] Cathcart J, Pulkoski-Gross A, Cao J. Targeting matrix metalloproteinases in cancer: bringing new life to old ideas. Genes Dis 2015;2(`1):26e34. [81] Bieliuniene E, Frøkjær JB, Pockevicius A, Kemesiene J, Lukosevicius S, Basevicius A, Barauskas G, Dambrauskas Z, Gulbinas A. Magnetic resonance imaging as a valid noninvasive tool for the assessment of pancreatic fibrosis. Pancreas 2019;48(1):85e93. [82] Su Y, Deng L, Yang L, Yuan X, Xia W, Liu P. Magnetic resonance imaging for the non- invasive diagnosis in patients with ovarian cancer: a protocol for systematic review and meta-analysis. Medicine (Baltim) 2020;99(50):e23551. [83] Ding H, Wu F. Image guided biodistribution and pharmacokinetic studies of theranostics. Theranostics 2012;2(11):1040e53. [84] Mulder WJ, Strijkers GJ, Griffioen AW, van Bloois L, Molema G, Storm G, Koning GA, Nicolay K. A liposomal system for contrast-enhanced magnetic resonance imaging of molecular targets. Bioconjugate Chem 2004;15(4):799e806. [85] Kim D, Jeong YY, Jon S. A drug-loaded aptamer-gold nanoparticle bioconjugate for combined CT imaging and therapy of prostate cancer. ACS Nano 2010;4(7):3689e96. [86] Zhu J, Zheng L, Wen S, Tang Y, Shen M, Zhang G, Shi X. Targeted cancer theranostics using alpha-tocopheryl succinate-conjugated multifunctional dendrimer-entrapped gold nanoparticles. Biomaterials 2014;35(26):7635e46. [87] Vasudev NS, Reynolds AR. Anti-angiogenic therapy for cancer: current progress, un- resolved questions and future directions. Angiogenesis 2014;17(3):471e94. [88] Mendes LP, Lima EM, Torchilin VP. Drug delivery in cancer. In: Handbook of nano- materials for cancer theranostics. Elsevier Inc; 2018. https://doi.org/10.1016/B978-0-12- 813339-2.00009-8. [89] Han N, Yang YY, Wang S, Zheng S, Fan W. Polymer-based cancer nanotheranostics: retrospectives of multi-functionalities and pharmacokinetics. Curr Drug Metabol 2013; 14(6):661e74. 22 Design and Applications of Theranostic Nanomedicines
- 36. [90] Sachdev A,Matai I, Gopinath P. Carbon dots incorporated polymeric hydrogels as multifunctional platform for imaging and induction of apoptosis in lung cancer cells. Colloids Surf B Biointerfaces 2016;141:242e52. [91] Xing H, Hwang K, Lu Y. Recent developments of liposomes as nanocarriers for thera- nostic applications. Theranostics 2016;6(9):1336e52. [92] Muthu MS, Feng SS. Theranostic liposomes for cancer diagnosis and treatment: current development and pre-clinical success. Expet Opin Drug Deliv 2013;10(2):151e5. [93] Soares DCF, De Sousa GF, De Barros ALB, Cardoso VN, De Oliveira MC, Ramaldes GA. Scintigraphic imaging and increment in mice survival using theranostic liposomes based on Gadolinium-159. J Drug Deliv Sci Technol 2015;30:7e14. [94] Al-Jamal WT, Kostarelos K. Liposomes: from a clinically established drug delivery system to a nanoparticle platform for theranostic nanomedicine. Acc Chem Res 2011; 44(10):1094e104. [95] Fahmy TM, Fong PM, Park J, Constable T, Saltzman WM. Nanosystems for simulta- neous imaging and drug delivery to T cells. AAPS J 2007;9(2):E171e80. [96] Bosman AW, Janssen HM, Meijer EW. About dendrimers: structure, physical properties, and applications. Chem Rev 1999;99(7):1665e88. [97] Jansen JF, de Brabander-van den Berg EM, Meijer EW. Encapsulation of guest molecules into a dendritic box. Science 1994;266(5188):1226e9. [98] Liu X, Wang C, Liu Z. Protein-engineered biomaterials for cancer theranostics. Adv Healthc Mater October 2018;7(20):e1800913. [99] Silva CO, Pinho JO, Lopes JM, Almeida AJ, Gaspar MM, Reis C. Current trends in cancer nanotheranostics: metallic, polymeric, and lipid-based systems. Pharmaceutics 2019;11(1):22. [100] Zhang Q, Yang M, Zhu Y, Mao C. Metallic nanoclusters for cancer imaging and therapy. Curr Med Chem 2018;25(12):1379e96. [101] Link S, El-Sayed MA. Shape and size dependence of radiative, non-radiative and pho- tothermal properties of gold nanocrystals. Int Rev Phys Chem 2000;19(3):409e53. [102] Kumar R, Korideck H, Ngwa W, Berbeco RI, Makrigiorgos GM, Sridhar S. Third generation gold nanoplatform optimized for radiation therapy. Transl Cancer Res 2013; 2(4). https://doi.org/10.3978/j.issn.2218-676X.2013.07.02. [103] Han G, Martin CT, Rotello VM. Stability of gold nanoparticle-bound DNA toward biological, physical, and chemical agents. Chem Biol Drug Des 2006;67(1):78e82. [104] Nandwana V, De M, Chu S, Jaiswal M, Rotz M, Meade TJ, Dravid VP. Theranostic magnetic nanostructures (MNS) for cancer. Cancer Treat Res 2015;166:51e83. [105] Zhu L, Zhou Z, Mao H, Yang L. Magnetic nanoparticles for precision oncology: thera- nostic magnetic iron oxide nanoparticles for image-guided and targeted cancer therapy. Nanomedicine January 2017;12(1):73e87. [106] Bobo D, Robinson KJ, Islam J, Thurecht KJ, Corrie SR. Nanoparticle-based medicines: a review of FDA-approved materials and clinical trials to date. Pharm Res (N Y) 2016; 33(10):2373e87. [107] Liu J, Liu T, Pan J, Liu S, Lu GQM. Advances in multicompartment mesoporous silica micro/nanoparticles for theranostic applications. Annu Rev Chem Biomol Eng 2018;9: 389e411. [108] Mishra D, Hubenak JR, Mathur AB. Nanoparticle systems as tools to improve drug delivery and therapeutic efficacy. J Biomed Mater Res December 2013;101(12): 3646e60. Theranostic nanostructures as nanomedicines: benefits, costs, and future challenges 23
- 37. [109] Nayak AK,Alkahtani S, Hasnain MS. Biomedical nanocomposites. In: Nayak AK, Hasnain MH, editors. Biomedical composites-perspectives and applications. Switzerland AG: Springer International Publishing, Springer Nature; 2021. p. 35e69. [110] Hasnain MS, Nayak AK. Nanocomposites for improved orthopedic and bone tissue en- gineering applications. In: Inamuddin, Asiri AM, Mohammad A, editors. Applications of nanocomposite Materials in orthopedics, woodhead publishing series in biomaterials. United States: Elsevier Inc.; 2019. p. 145e77. [111] Hasnain MS, Ahmad SA, Chaudhary N, Hoda MN, Nayak AK. Biodegradable polymer matrix nanocomposites for bone tissue engineering. In: Inamuddin, Asiri AM, Mohammad A, editors. Applications of nanocomposite Materials in orthopedics, wood- head publishing series in biomaterials. United States: Elsevier Inc.; 2019. p. 1e37. [112] Shen X, Li T, Chen Z, Geng Y, Xie X, Li S, Yang H, Wu C, Liu Y. Luminescent/ magnetic PLGA-based hybrid nanocomposites: a smart nanocarrier system for targeted codelivery and dual-modality imaging in cancer theranostics. Int J Nanomed 2017;12: 4299e322. [113] Wu J, Jiang W, Shen Y, Jiang W, Tian R. Synthesis and characterization of mesoporous magnetic nanocomposites wrapped with chitosan gatekeepers for pH-sensitive controlled release of doxorubicin. Mater Sci Eng C Mater Biol Appl 2017;70(Pt 1):132e40. [114] Kievit FM, Zhang M. Cancer nanotheranostics: improving imaging and therapy by tar- geted delivery across biological barriers. Adv Mater 2011;23(36):H217e47. [115] Bhaumik J, Mittal A, Banerjee A, Chisti Y, Banerjee UC. Applications of photo- theranostic nanoagents in photodynamic therapy. Nano Res 2014;8:1373e94. [116] Hussien NA, Isıklan N, Turk M. Pectin-conjugated magnetic graphene oxide nanohybrid as a novel drug carrier for paclitaxel delivery. Artif Cell Nanomed Biotechnol 2018: 1e10. [117] Popat A, Karmakar S, Jambhrunkar S, Xu C, Yu C. Curcumin-cyclodextrin encapsulated chitosan nanoconjugates with enhanced solubility and cell cytotoxicity. Colloids Surf B Biointerfaces 2004;117:520e7. [118] Roma-Rodrigues C, Pombo I, Raposo L, Pedrosa P, Fernandes AR, Baptista PV. Nanotheranostics targeting the tumor microenvironment. Front Bioeng Biotechnol 2019; 7:197. [119] Yao J, Yang M, Duan Y. Chemistry, biology, and medicine of fluorescent nanomaterials and related systems: new insights into biosensing, bioimaging, genomics, diagnostics, and therapy. Chem Rev 2014;114(12):6130e78. [120] Lee J, Jeong EJ, Lee YK, Kim K, Kwon IC, Lee KY. Optical imaging and gene therapy with neuroblastoma-targeting polymeric nanoparticles for potential theranostic applica- tions. Small 2016;12(9):1201e11. [121] Shao D, Li J, Pan Y, Zhang X, Zheng X, Wang Z, Zhang M, Zhang H, Chen L. Noninvasive theranostic imaging of HSV-TK/GCV suicide gene therapy in liver cancer by folate-targeted quantum dot-based liposomes. Biomater Sci 2015;3(6):833e41. [122] Singh AV, Sitti M. Targeted drug delivery and imaging using mobile milli/microrobots: a promising future towards theranostic pharmaceutical design. Curr Pharmaceut Des 2016; 22(11):1418e28. [123] L€ utje S, Rijpkema M, Franssen GM, Fracasso G, Helfrich W, Eek A, Oyen WJ, Colombatti M, Boerman OC. Dual-modality image-guided surgery of prostate cancer with a radiolabeled fluorescent anti-PSMA monoclonal antibody. J Nucl Med 2014;55(6): 995e1001. 24 Design and Applications of Theranostic Nanomedicines
- 38. Theranostic nanogels: designand applications 2 Mayra A. Mendez-Encinas 1 and Elizabeth Carvajal-Millan 2 1 Department of Chemical Biological and Agropecuary Sciences, University of Sonora, Avenida Universidad e Irigoyen, Caborca, Sonora, Mexico; 2 Biopolymers, Research Center for Food and Development, CIAD A.C., Carretera Gustavo E. Astiazaran Rosas No. 46, Hermosillo, Sonora, Mexico 2.1 Introduction Theranostics comprise those novel strategies combining disease diagnosis and therapy for a broad range of applications in the field of medicine. Nanotechnology has offered an opportunity to develop systems that combine diagnosis and therapy for theranostic purposes. Nanoformulations are considered excellent systems for use in theranostic ap- plications because they can improve the biodistribution and the target site accumula- tion of the administered therapeutic agent [1]. Nanotheranostics refers to the application of nanomedicine strategies for the development of novel nanoformulations-based systems that combine disease diagnosis and targeted- delivery of therapeutics simultaneously in a single platform. The main objective of these theranostic systems is to treat and diagnose the disease at an early stage [2]. Theranostic nanoformulations consist of colloidal nanoparticles (NPs) ranging in sizes from 10 to 1000 nm made from macromolecular materials/polymers in which the diag- nostic and therapeutic agent are encapsulated, entrapped, conjugated, or adsorbed for diagnosis and treatment simultaneously at cellular and molecular level [2]. The thera- peutic agents include hydrophobic organic drugs, proteins, peptides, and genetic ma- terial, while the diagnostic agents are those used for optical imaging, magnetic resonance imaging, nuclear imaging, ultrasound imaging, among others [2]. Several NPs have been explored as platforms for theranostic purposes including metallic NPs, mesoporous silica particles, carbon-based NPs, and polymeric nanogels [3]. Among these, nanogels have demonstrated to be an attractive choice for theranostic applications. This chapter focuses on describing different designs of theranostic nano- gels based on the principal methods used for imaging. Moreover, the application of these theranostic nanogels is discussed. 2.2 Nanogels Nanogels (NGs) are hydrogels or particles with a submicron size ranging from 20 to 200 nm composed of three-dimensional cross-linked polymers networks that exhibit Design and Applications of Theranostic Nanomedicines. https://doi.org/10.1016/B978-0-323-89953-6.00003-9 Copyright © 2023 Elsevier Ltd. All rights reserved.
- 39. high water absorptioncapacity [4]. These materials have gained increased attention in the biomedical field due to their attractive properties. The properties of NGs include biocompatibility and biodegradability, easy and higher drug loading capacity, stability of entrapped drug, physical stability, swelling capacity in aqueous media, versatility in design and easy formulation, and others [5,6]. Besides, NGs exhibit stimuli-responsive nature, permeability, and small particle size, as well as the ability to control the release of a wide variety of bioactive molecules making them materials with suitable charac- teristics for drug delivery systems [5,6]. Fig. 2.1 shows the most relevant attributes of NGs for their application as drug delivery systems. NGs can be prepared through different methods such as in situ polymerization and cross-linking of hydrophilic monomers, or via cross-linking of hydrophilic copolymers containing functional groups using cross-linkers [7,8]. The bioactive molecules, which are usually drugs, can be loaded into the NG via physical or chemical interactions between the molecule and the functional groups in the polymer network [6]. Moreover, the incorporation of ligands into the gel structure allows a high selectivity and a target-site drug delivery, preventing the accumulation of drug in unspecific sites [9]. According to the method of preparation and type of linkages formed in the cross- linked polymeric network, NGs can be classified as physically cross-linked NGs and chemically cross-linked NGs. Physically cross-linked NGs involve non-covalent type interactions (hydrogen bonds, electrostatic interactions, van der Waals forces, etc.) between the polymer chains forming the three-dimensional polymer network Figure 2.1 Attributes of NGs for their application as drug delivery systems. 28 Design and Applications of Theranostic Nanomedicines
- 40. [6,9]. On theopposite, chemically cross-linked NGs are formed by covalent cross- linked polymer networks, where a cross-linking agent (chemical or enzymatic) is needed to join the polymer chains [9]. Due to their covalent nature consisting of disul- fide or amine based bonds, and sometimes via enzymatic or photo-induced cross- linking, chemical NGs are stronger and more stable than physical gels [6]. Due to their versatility, NGs are suitable for numerous applications in the biomed- ical field, including tissue engineering, wound healing, drug delivery, bioimaging, among others. However, one of their most promising applications is as drug delivery systems due to their physicochemical and biological properties that allow them to achieve a site-specific delivery of the entrapped drug [10]. In addition, they can be administered through different routes including oral, pulmonary, nasal, intraocular, nasal, and parenteral [9]. Thus, NGs as drug delivery systems can be exploited for different purposes including the treatment of different diseases, gene therapy, inflam- matory disorders, tissue engineering, and others (Fig. 2.2) [4]. 2.3 Theranostic nanogels Recently, NGs have been extensively explored for theranostic applications. NGs pro- vide extraordinary advantages for application as theranostic platforms in comparison to other systems such as micelles, liposomes, and others [11]. Some of these features Figure 2.2 Biomedical applications of NGs. Adapted from Sabir F, Asad MI, Qindeel M, Afzal I, Dar MJ, Shah KU, et al. Polymeric nanogels as versatile nanoplatforms for biomedical applications. J Nanomater 2019. Theranostic nanogels: design and applications 29
- 41. are their highbiocompatibility and biodegradability, high drug loading capacity, con- trol release ability, swelling capacity, among others [12]. Besides their high stability and facile dispersibility, NGs allow the incorporation of both diagnostics (imaging agents) and therapeutic agents (drugs, biomolecules) in a single platform [13]. The modification of the NG structure through the incorporation of functional groups allows the development of NGs with stimuli-response capacity that can react to different stim- ulus such as pH, temperature, light, magnetic field, and redox environment [14]. Thus, stimuli-responsive NGs respond to either endogenous or exogenous stimulus providing an effective biodistribution and controlled release of bioactive agents at target sites [15], being therefore an excellent tool for theranostic purposes. Theranostic NGs are systems consisting of an imaging component, a therapeutic agent and a targeting ligand [3]. The therapeutic agents which are usually drugs, genes, or photosensitizers can be incorporated into the NG by physical entrapment or chem- ical conjugation methods [16]. The diagnostic agents and the targeting ligands are con- jugated in the surface of the NG structure [17]. The imaging function of NG systems can be accomplished by its loading or conjugation with imaging agents such as dots, organic dyes, radiolabels, and magnetic particles [3]. In this sense, different imaging techniques have been explored for diagnostics in theranostics applications, including optical imaging, magnetic resonance imaging (MRI), ultrasound imaging (USI), pho- toacoustic imaging (PAI), nuclear imaging, single photon emission computed tomog- raphy (SPECT), and others [15]. Typically, external imaging agents (quantum dots, organic dyes, radiolabels, and MRI contrast agents) are loaded into the gel along with the therapeutic agent during the NG preparation in order to create a simultaneous diagnosis and therapeutic system [3]. Because sometimes a premature leakage of the image agent before the NG reaches the target site can occur resulting in an unspecific biodistribution of the drug and a potential toxicity [14], novel NGs with innate imaging potential have also been designed in order to avoid these drawbacks [3]. Theranostic NGs have been mainly studied for application in cancer diagnosis and imaging-guided cancer therapy [6,11]. In the field of cancer treatment, the use of powerful diagnostic methods that permit a real-time monitoring of the therapeutic process may provide a precise and personalized treatment [11]. Therefore, the interest in the development of imaging-guided cancer therapeutic systems has increased in the last years. 2.4 Designs of theranostic nanogels Nowadays, the increasing progress in material sciences have provided all tools required for the designing of a wide variety of theranostic systems. The designs of a theranostic NG will mainly depend on the desired purposes and the method used for its preparation. Depending on the nature of the materials constituting the system, NGs can be clas- sified based in organic and organic/inorganic (hybrid) NGs (Fig. 2.3). Organic NGs are considered those prepared by cross-linking functional macromolecules which were previously synthesized through the modification of their functional groups. The other 30 Design and Applications of Theranostic Nanomedicines
- 42. type of NGsconsist in inorganic NPs coated with cross-linked organic shells. Due to their nature, inorganic NPs are poor biocompatible and highly unstable under physio- logical conditions, being therefore necessary coating their surfaces with biocompatible materials. Thus, the entrapment of these inorganic particles into NGs to form core-shell structures help to enhance considerably their stability and biocompatibility [11]. The diagnostic function of the theranostic NG will also have an important influence on the theranostic platforms’ design as it determines the most appropriate diagnostic agent for the desired purposes. Besides, once the diagnostic agent has been selected, it is necessary to establish the adequate imaging tools to assure an optimum diagnostic function. Several imaging modalities have been incorporated into NGs to accomplish the diagnostic function, including optical imaging, MRI, PAI, USI, and others. More- over, the development of multimodal nanoplatforms incorporating two or more imag- ing modes have gained attention. Bioimaging is a novel noninvasive technique used to observe the biological behavior over a given period of time without disturbing the life cycles (movement and respiration, etc.) with the objective of recording the specimen’s 3D structure with minimal inconvenience. This method is very useful in linking sub- cellular structure observations and all tissues in multicellular organism [18]; therefore, it has been widely used in several clinical applications. In the next section, the char- acteristics and applications of theranostic NGs are described based on the imaging technique used for the diagnostic purposes. Figure 2.3 Schematic illustration for preparation of cross-linked NGs. (a) Preparation of macromolecules-based cross-linked NGs. (b) Preparation of inorganic NPs-based cross-linked NGs. Adapted from Zhou W, Yang G, Ni X, Diao S, Xie C, Fan Q. Recent advances in crosslinked nanogel for multimodal imaging and cancer therapy. Polymers 2020;12(9). Theranostic nanogels: design and applications 31
- 43. 2.4.1 Optical imaging Fortheranostic purposes, optical imaging is among the most commonly used tech- niques for bioimaging due to their multiple advantages including high safety and sensi- tivity, low cost and capability of multichannel imaging [11,19]. These systems, called phototheranostics, based on optical imaging have demonstrated promising expectative for application mainly in cancer imaging and therapy [11]. Optical fluorescence can be categorized according to the emission wavelength in near-infrared (NIR, 750e1000 nm), visible light (450e750 nm), and ultraviolet (320e450 nm) [19]. Several imaging agents including fluorescent dyes, quantum dots, and metallic NPs can be incorporated into the NG system for detection by optical imaging. In addition, the development of novel NGs with innate fluorescence have been explored. NGs incorporating this imaging modality have been widely studied using in vitro as well as in vivo models in order to prove their potential application in imaging-guided cancer treatment. Table 2.1 shows some theranostic NGs designed for diagnostic based on op- tical imaging techniques. Recently, the theranostic research field has increased its interest in NGs systems where the use of external imaging agents is not necessary. There are some concerns related to the stability of the bonds formed during the conjugation of imaging agents into the NG surface. The exposure of these systems to certain physiological conditions such as enzymes or pH changes could lead to the break of the bonds and subsequent loss of the imaging agent before reaching the target site [3]. Organic dyes and quantum dots are among the fluorescence probes most widely used that can be encapsulated within or conjugated to the NP system. However, some of their disadvantages are that organic dyes exert poor photochemical stability and exert rapid photo bleaching, while the metals cadmium and selenide contained in quantum dots are toxic to organ- isms [20]. For these reasons, the exploration of new materials with intrinsic or innate fluorescence has greatly increase in the last years. Gyawally et al. [20] developed a highly photostable NG for fluorescence-based theranostics. The NG was prepared us- ing biocompatible monomers (citric acid, maleic acid, L-cysteine, and PEG) and its surface functionalized with RGD (Arg, Gly, Asp) peptides and encapsulated with an anticancer drug (DOX). The system exhibited pH-responsive controlled drug release in acidic pH tumor environment and strong fluorescence allowing tracking of targeted drug delivery in cytoplasmic regions of prostate cancer cells to induce cell death. The system demonstrated to be a strong candidate for theranostic medicine due to its high stability and capacity for real-time fluorescence-based monitoring drug delivery. In a similar way, Vijayan et al. [17] designed a novel theranostic probe by conjugating octreotide (natural growth hormone) with an NIR-emitting NG (PMB-OctN). The fluo- rescent NG, synthetized based on photoluminiscent cromacromer (PEG-maleic acid-4 aminobenzoic), diethylene glycoldimethacrylate, and octreotide was loaded with DOX in order to construct the theranostic probe. The PMB-OctN demonstrated NIR imaging capability and increased cellular uptake in cervical cancer cells. Moreover, in vivo studies using mice revealed longer in vivo circulation lifetime. The results suggested this system as a promising candidate for theranostic purposes. 32 Design and Applications of Theranostic Nanomedicines
- 44. Table 2.1 TheranosticNGs platforms using optical imaging modality for diagnostic function. Theranostic NG design Imaging agent Therapeutic agent/method In vitro/ in vivo model References Clickable NGs via thermally driven self- assembly of polymers Thiol-bearing hydrophobic dye (BODIPY- SH) and N- (fluoresceinyl) maleimide Cyclic-peptide-base targeting group (cRGDfC) MDA-MB- 231 breast cancer cells [8] Highly photostable NG for fluorescence- based theranostics Innate fluorescence DOX Prostate cancer cells [20] Alginate-based cancer- associated, stimuli-driven and turn-on theranostic prodrug NGs Rhodamine B DOX HepG2 cells [21] Theranostic alginate- based cisplatin- loaded NGs Fluorophore ATTO655 Cisplatin Macrophage cell line J7744.1 [22] HDMVECn (normal cell line) Multifunctional NG with reversible and nonreversible linkages Cy5 dye DOX MDA-MB- 231 breast cancer cells [13] Magneto- fluorescent hybrid polymer NG for theranostic applications Innate fluorescence Superparamagnetic iron oxideNPs (SPION) Murine model and HeLa cells [23] Hyperthermia effect Responsive hyaluronic acid-gold clusters hybrid NG theranostic system Gold NPs DOX A549, NIH3T3 and H22 cell lines [24] H22 tumor- bearing mice Continued Theranostic nanogels: design and applications 33
- 45. The modification offunctional groups in polymers is very common in the designing of theranostic systems as it improves their properties for specific purposes. The design and synthesis of NGs with diverse chemical compositions allows the incorporation of various functional groups which are able to bind molecules of interest that provide certain properties to the system [13]. In this sense, the interest in developing multifunc- tional NGs which combine different properties has gained attention in the last years. In a previous study, an alginate-based multifunctional theranostic prodrug NG was designed with potential for tumor diagnosis and chemotherapy [21]. For this purpose, the NG was prepared by cross-linking the folate-terminated PEG (FA-PEG-NH2) and rhodamine B (RhB)-terminated PEG (RhB-PEG-NH2) modified oxidized alginate with cystamine, following conjugation with DOX. The folate-receptor-mediated tar- geting and pH/reduction dual responsive intracellular triggered a desirable release of DOX allowing the killing of cancer cells. In addition, due to the RhB groups, the NGs expressed strong fluorescence only in acidic media, similar to tumor microenvi- ronment, therefore being optimum systems for real-time and noninvasive location tracking to cancer cells. When designing theranostic platforms, several strategies can be combined with the objective of increasing the specificity of the system. The stimuli-responsive property is desirable in theranostic platforms. In “smart” nanocarriers, the release of the encapsu- lated bioactive agent can be triggered by various stimuli (temperature, pH, enzymes, redox, hypoxia environment, etc.). In order to improve the efficacy of these systems for cancer therapy, the incorporation of receptors-mediated cancer cell uptake is Table 2.1 Theranostic NGs platforms using optical imaging modality for diagnostic function.dcont’d Theranostic NG design Imaging agent Therapeutic agent/method In vitro/ in vivo model References Fucoidan-based theranostic NG Chlorin e6 Fucoidan HT1080 human fibrosar coma cell line [25] Male BALB/ c nude mice Octreotide conjugated fluorescent PEGylated polymeric NG for theranostic applications Innate fluorescence DOX HeLa cells [17] Mice DOX, doxorubicin; NG, nanogel; NPs, nanoparticles; PEG, polyethylene glycol 34 Design and Applications of Theranostic Nanomedicines
- 46. considered another goodstrategy. In this sense, Lin et al. [24] synthetized a responsive hyaluronic acid-gold clusters hybrid NG theranostic system with the ability of responding to the reducing microenvironment, activating tumor targeting and light traceable cancer therapy. The NGs were prepared by copolymerization in aqueous me- dium of hyaluronic acid (HA) with vinyl group and cystamine bisacrylamide (CBA). Then, the multifunctional mHA-gold clusters hybrid NGs (mHA-GC hybrid NGs) were obtained by in situ reduction of gold salts in the HA NGs. The highly selective cancer cells uptake and intratumoral accumulation of the NGs were demonstrated by their fluorescence tracking. The drug release was triggered by the massive glutathione (GSH) production in cancer cells which allowed disassembly of the NG. Moreover, the antitumor activity of DOX was evidenced by tumor cell suppression through both in vitro an in vivo studies. These findings suggested the targeted drug delivery and con- trol release of antitumor drug with light-traceable monitoring abilities of these plat- forms in cancer treatment. In another study performed by Cho et al. [25], a fucoidan-based theranostic NG (CFN-gel) was synthetized to achieve activatable NIR fluorescence imaging of tumor site and enhanced photodynamic therapy (PDT) (Fig. 2.4). The CFN-gel had affinity for P-selectin, which is overexpressed on the sur- face of tumor neovascular endothelial cells, thus providing an enhanced targeting. Due to its aggregation-induced self-quenching in response to redox potential, this system recovered its photoactivity only after internalization into cancer cells, enabling a selec- tive NIR fluorescence imaging and an enhanced photodynamic of tumors. The CFN- gel also showed antitumor effect in the absence of light treatment in vivo as fucoidan Figure 2.4 Schematic illustration of CFN-gel and its mode of action. EPR, enhanced permeation and retention. Adapted from Cho MH, Li Y, Lo PC, Lee H, Choi Y. Fucoidan-based theranostic nanogel for enhancing imaging and photodynamic therapy of cancer. Nano-Micro Lett [Internet] 2020; 12(1):1e15. Available from https://doi.org/10.1007/s40820-020-0384-8. Theranostic nanogels: design and applications 35
- 47. can inhibit thebinding of the vascular endothelial growth factor (VEGF), a key angio- genesis promoting molecule, to its cell membrane receptor. The observations indicated that the CFN-gel could be a new theranostic material for imaging and treating cancer. In order to exert the diagnostic function, theranostic systems need to include different materials such as iron oxide NPs, quantum dots, gold NPs, and others [26]. Superparamagnetic iron oxide NPs (SPION) are able to perform both imaging and therapy through MRI and hyperthermia effect [27]. SPION are capable to destroy cancer cells through the conversion of an alternating high-frequency magnetic field into thermal energy, a phenomenon known as magnetic hyperthermia [23]. Taking advantage of these properties, Vijayan et al. [23] created a magneto-fluorescent hybrid polymer NG for theranostic applications. The system consisting of a core-shell morphology (SPION core and PEG shell) revealed good cancer fluorescence capability and exerted hyperthermia effect evidenced by the cancer cells lysis. In addition, the NG was assessed using a murine model showing good NIR imaging capability and demonstrating promising future potential for cancer theranostic applications. 2.4.2 Magnetic resonance imaging The use of magnetic resonance imaging (MRI) as a tool for diagnostic component has also been studied for theranostic applications. Although this tool provides low ionizing radiation exposure, high anatomical resolution and great soft tissue resolution, it pre- sents certain disadvantages such as low sensitivity and poor contrast that limit its use in cancer diagnostic [28]. The use of contrast agents in MRI is highly used to overcome these problems as they can alter the relaxation times of protons in different organs by their involvement with the external magnetic field [29]. In MRI, the contrast agents more commonly used are gadolinium (Gd) chelates and iron oxide particles such as SPION [19]. Sometimes, the use of contrast agent aggregates does not provide a pre- cise imaging of the tumor due to their low molecular weight, being therefore necessary large doses that significantly increase the risk of systemic toxicity [15]. These draw- backs can be solved by encapsulating or chelating the contrast agents in NPs. In this sense, recent investigations have been focused in developing of theranostic NGs using MRI techniques (Table 2.2). Peng et al. [30] designed a hybrid NG with magnetic and dual responsive proper- ties consisting in an alginate coated SPION system. The alginate coating responded to high concentration of GSH and acidic microenvironment of tumor cells, while the SPION core provided MRI properties. In addition, the anticancer drug DOX was encapsulated into the system. The NGs exhibited magnetic-targeted characteristics, high drug loading capacity, co-triggered release behavior, high toxicity to tumor cells and MRI functions. The authors concluded that these systems have great potential as tumor-targeting nano-theranostic agents for simultaneous MRI and efficient anti- tumor treatment. In a similar way, Chen et al. [32] created a multifunctional system consisting in a hybrid FeeO4-poly(acrylic acid) NG for both drug delivery and MRI. The hybrid NGs showed high drug (DOX) loading capacity and sustained drug release. The NGs were able to penetrate the plasma membrane of SH-SY5Y cells, suggesting their good attributes as carriers for drug delivery. Moreover, the cyclic 36 Design and Applications of Theranostic Nanomedicines
- 48. RGD peptide wasconjugated to the surface of the NG to target integrin avb3, a pro- tein expressed on cancer cell membranes. Besides, the ability of cyclic RGD-coated NGs to target integrin avb3 was assessed in vivo by MRI with mice bearing- hepatocarcinoma tumors. MRI studies revealed that the NGs reach the tumor site showing the specificity of the particle targeting in vivo. The results suggested that the hybrid NG presents suitable properties for practical applications in simultaneous drug delivery, tumor diagnostics and targeted therapy. Zou et al. [34] also designed a polyethylenimine (PEI)-based hybrid NG incorporated with ultrasmall iron oxide NP and DOX (Fe3O4/PEI-Ac NGs/DOX) for MRI-guided chemotherapy of tumor (Fig. 2.5). The hybrid NGs showed pH-dependent release of DOX and were taken up by cancer cells in vitro. Moreover, they exerted an inhibitory effect on tumor growth which was evidenced by MRI. Table 2.2 Theranostic NGs systems using magnetic resonance imaging for diagnostic purposes. Theranostic platform Imaging agent Therapeutic agent Application References Novel dual responsive alginate-based magnetic NGs for oncotheranostics SPION DOX HepG cells [30] Magnetic and thermoresponsive NGs for NIR-triggered chemotherapy Iron oxide NPs DOX Murine model and HeLa cells [31] Hybrid Fe-O4- poly(acrylic acid) NG for both drug delivery and MRI SPION DOX Murine hepatic carcinoma H22 cells and SH-SY5Y cells [32] Core-shell NPs for MRI- guided thermochemotherapy Iron oxide NPs DOX Human ovary cancer cell (HAC-2) and mice bearing ovarian cancer [33] Polyethylenimine NG incorporated with ultrasmall iron oxide NPs and DOX for MRI-guided chemotherapy of tumor Fe3O4 NPs DOX 4T1 cancer cells (mammary carcinoma cell line from the mammary gland tissue of a mouse) [34] 4T1 tumor- bearing mice DOX, doxorubicin; SPION, superparamagnetic iron oxide NPs. Theranostic nanogels: design and applications 37
- 49. Magnetic hyperthermia asa new thermotherapy facilitates the treatment of deep tu- mors at a local level because the magnetic particles only produce the heat in a specific area and the alternate magnetic field can penetrate deep within the body [33]. Thus, the implementation of MRI-guided magnetic termochemotherapy appears to be a novel technique that can be used to improve the therapeutic effect. In a previous work, Hay- ashi et al. [33] developed a core-shell system where the magnetic iron oxide NPs were entrapped into the polymer network. The NG system accumulated in abdomen tumors facilitating their visualization by MRI. The exposure of the NG system to an alter- nating magnetic field induced heat generation allowing the release of the entrapped drug within the tumor and causing their growth inhibition. These findings indicated that core-shell magnetic termochemotherapy could exert better therapeutic efficacy that both magnetic hyperthermia and chemotherapy as individual treatments. Biglione et al. [31] designed a magnetic thermoresponsive NG for NIR triggered chemotherapy. The system consisted of an NG with dispersed iron oxide NPs on its polymer (oligo- ethylene glycol methacrylate) network. Because the iron oxide NPs are capable of transducing NIR light into heat and can be used as MRI contrast agents due to their paramagnetic properties, the system showed a successful NIR-triggered chemo- therapy. The system produced hyperthermia created by the light-to heat conversion of the magnetic particles exposed to NIR irradiation and showed an antiproliferative effect on HeLa cells in vitro due to the release of the encapsulated drug (DOX). In addition, the NIR-chemotherapy effect of the system was demonstrated through in vivo studies by MRI. The observations indicated that this hybrid NG can be used for photothermal therapy as well as for MRI, therefore being good candidate for thera- nostic devices. Figure 2.5 Schematic representation of the synthesis of Fe3O4/PEI-Ac NGs/DOX complexes for MRI-guided chemotherapy of tumors. BIS, N,N0-methylene-bis(acrylamide); EDC, 1- ethyl-3-(3-(dimethylamino)propyl) carbodiimide hydrochloride. Adapted from Zou Y, Li D, Wang Y, Ouyang Z, Peng Y, Tom as H, et al. Polyethylenimine nanogels incorporated with ultrasmall iron oxide nanoparticles and doxorubicin for MR imaging-guided chemotherapy of tumors. Bioconjug Chem 2020;31(3):907e15. 38 Design and Applications of Theranostic Nanomedicines
- 50. 2.4.3 Ultrasound imaging Ultrasoundimaging (USI) has become a very attractive diagnostic method due to its low cost and multiple advantages. USI is a real-time noninvasive method in which the tissues reflect the transmitted sound waves and are converted to pictures by a con- verter [15]. High intensity focused ultrasound (HIFU) is a safe and feasible technique that can be employed as a novel theranostic tool for simultaneous imaging and site- specific therapy [35]. HIFU is capable of inducing tissue necrosis through the conver- sion of US energy to hyperthermia when focused [35]. The use of NPs loading with US-sensitive molecules is commonly used to intensify the HIFU ablation effects on tumors. Moreover, the aggregation of the NPs in tumor tissue promotes the acoustic impedance and favors the USI [35]. Recently, a ternary inorganic-supramolecular- polymeric NG was designed as a multifunctional nanotheranostic agent for combined USI and imaging-guided HIFU therapy [36]. The multifunctional NGs were synthe- tized by the in situ amidation-fueled self-assembly and laccase-mediated post-cross- linking and loaded with DOX and perfluorohexane as therapeutic and US-sensitive guest molecules (MSN-GII-PFH). In vitro evaluation demonstrated that the NGs can be taken up by the tested cells (human liver hepatocellular carcinoma SMMC-7721 cells and human hepatocytes LO2 cells) and show low cytotoxicity, being therefore suitable for in vivo USI and US-mediated chemotherapy. In vivo studies performed in rabbits bearing-liver tumor indicated that the system responded efficiently to US irradiation as evidenced by good USI (Fig. 2.6). In addition, the high efficacy of the Figure 2.6 In vivo applications: The schematic illustration of the USI-guided HIFU therapy (a) and US images (b), as well as the corresponding average gray values (c) of VX2 tumors in rabbit livers before and after intravenous injection of MSN-GII-PFH at various time intervals (30 min, 1 h) and post therapy. Each column is the average of three experiments (** and *** represent significant differences in the average gray values by comparing the different samples at P 0.01 and P 0.001). The tumors are marked by yellow arrows. Adapted from Wang X, Qiao L, Yu X, Wang X, Jiang L, Wang Q. Controllable formation of ternary inorganic-supramolecular-polymeric hydrogels by amidation-fueled self-assembly and enzymatic post-cross-linking for ultrasound theranostic. ACS Biomater Sci Eng 2019;5(11): 5888e96. Theranostic nanogels: design and applications 39
- 51. USI-guided HIFU therapywas evidenced by the observed enhanced imaging after tu- mor ablation. These findings demonstrated the potential application of this hybrid NG as nanotheranostic carrier for US-guided HIFU therapy. One of the main limitations of USI is the poor image contrast that stems from similar acoustic impedances between normal and abnormal soft tissues [37]. There- fore, in order to differentiate between normal and abnormal tissues, the use of US contrast agents to enhance US image represents a good alternative [35]. In this sense, the use of nanoscale gas-generating chemical systems capable of stimulus-responsive inflation to microbubbles has been employed as an echogenic strategy for enhancing USI. Heo et al. [37] reported a peroxamide-based US contrast agent as a H2O2-respon- sive gas (CO2)-generating system for diagnostic USI of inflammatory diseases. For this purpose, the authors prepared a hydrolytic degradation-resistant peroxamide NG. The interior of the peroxamide-concentrated NG served as a catalytic reactor for the H2O2- responsive gas generation as well as a gas reservoir capable of nano-to-micro inflation. The system could enhance the US contrast in response to H2O2 allowing to perform diagnostic USI of H2O2-overproducing inflammatory disease in mouse models. 2.4.4 Photoacoustic imaging Photoacoustic imaging (PAI) has become a promising technique for disease diagnosis due to its excellent spatial resolution and high optical contrast. In PAI, the tissue is exposed to a laser light, and it absorbs the light causing local heating and undergoes thermoelastic expansion, resulting in US waves, a phenomenon known as photoacous- tic effect [38]. The photoacoustic conversion is proportional to the optical absorption; therefore, the individual tissue constituents that absorb light at different wavelengths can be selectively imaged with PAI [38]. Photothermal therapy (PTT) is a novel method used in cancer therapy that can destruct cancer cells without damaging the sur- rounding healthy tissues [39] by the use of photothermal agents that convert light en- ergy into heat under laser radiation [40]. The photothermal agents can be used as contrast agents for PAI as they can absorb the pulsed light and the US waves generated can be detected using a special transductor [41]. Several photothermal agents are used in PAI-guided PTT including metal or inorganic NPs [42], conducting polymers [43,44], and other small molecules such as cyanine and porphyrin [45]. These agents are usually encapsulated to protect their stability and increase their circulation time in vivo. Zhou et al. [43] developed a polyaniline-loaded polyglutamic acid NG as a platform for PAI-guided tumor PTT (g-PGA/Cys@PANI NGs). The NGs exhibited excellent NIR absorbance providing good PAI contrast and photothermal conversion capacity. An in vitro study showed that the cells (4T1) treated with the NGs and exposed to irra- diation significantly reduced their viability, indicating their ability as photothermal agents. Besides, the efficacy of the system was assessed by in vivo studies on a xeno- grafted tumor model, observing good tumor PAI performance. The application of laser irradiation to rats injected with the NGs resulted in heat generation in the tumor region, suggesting the potential of these systems in PPT applications. Similarly, a thermo- responsive NG loaded with the photothermal transducing polymer polypyrrole for 40 Design and Applications of Theranostic Nanomedicines
- 52. combinational photothermal andchemotherapy along with PAI was designed by The- une et al. [44]. The synthetized NGs showed a dual-response for temperature and NIR light where the generated heat under irradiation exposure served for triggering the thermo-responsive network and for photothermal ablation of cancer. The NGs also allowed the determination of their biodistribution after administration ex vivo due to their abilities as photoacoustic contrast agents. Finally, in vivo studies demonstrated that the NGs efficiently inhibited the tumor growth due to the combination of chemo- therapeutic and photothermal treatment. 2.4.5 Positron emission tomography Positron emission tomography (PET) imaging and SPECT are both radionuclide im- aging techniques [15]. As imaging tool, PET is commonly used in oncology, neurology, and cardiology. Because this technique uses gamma rays which have the highest energy among imaging methods, it possesses high sensitivity providing excel- lent visualization and quantification of disease markers [19]. The tracers used for PET imaging usually include organic molecules such as 18 F and 11 C or metal radionuclide such as copper-64, yttrium-86, zirconium-89, and others [19] (Table 2.3). The radio- nuclide 99 Tc has shown good performance for SPECT imaging because it provides higher imaging resolution in comparison with other molecules such as 131 I [46,47]. In a previous study, Zhao et al. [48] elaborated a theranostic nanocomplex with enhanced blood-brain barrier penetrability and tumor-targeting efficiency for glioma SPECT imaging and anticancer drug delivery. The system was designed using branched PEI which was conjugated with glioma-targeting peptide chlorotoxin (CTX) and the radionuclide 99m Tc, and finally loaded with DOX. The nanosystem showed targeting specificity and therapeutic effect of DOX toward glioma cells in vitro and in vivo using a subcutaneous tumor mouse model. The radiolabeling of the NG with 99m Tc allowed the visualization of drug accumulation in tumors of glioma-bearing mice and the DOX delivery into the brains of rats through SPECT im- aging. The results demonstrated the potential of this nanosystem for facilitating glioma-targeting SPECT imaging and chemotherapy. Among the organic tracers, 18 F (fluorodeoxyglucose) which is a glucose analog is frequently used for oncological imaging because many tumors consume more glucose than surrounding tissues [49]. A novel nanocomplex comprising alginate NG co-loaded with cisplatin and Au NPs was designed by Mirrahimi et al. [50] for combined chemo-PTT. In vivo results using a CT26 tumor-bearing mice demonstrated that the administration of the NGs caused an evident tumor inhibition. The combined action of chemo-PTT suppressed the tumor growth up to 95% and prolonged the survival rate of mice in comparison to the control group. Moreover, the tracer 18 F was used to monitor the tumor metabolism by PET imaging, and the results showed that the administration of the NGs along with laser irradiation are capable of eradicating microscopic residual tumor to prevent cancer relapse. With the results observed, it was concluded that these systems have potent anticancer effect and may reduce considerably the side-effects associated to chemotherapy. Theranostic nanogels: design and applications 41
- 53. 2.4.6 X-ray computedtomography X-ray computed tomography (CT) is a widely used noninvasive imaging modality in the clinical field. It possesses high spatial resolution, high penetration providing precise anatomical information with reconstructed tridimensional imaging [52,53]. Among the contrast agents, more commonly used for CT imaging are iodinated small molecules [15]. Iodixanol, a contrast agent frequently used in CT imaging, has low osmolality and good tolerability [53]; however, it has nonspecific distribution and rapid renal clear- ance post injection [54]. Nanosized CT contrast agents represent a good alternative to avoid these limitations as they exhibit longer circulation time and site-specific accumula- tion [55]. Zhu et al. [55] prepared a bioresponsive and fluorescent hyaluronic acid- Table 2.3 Theranostic NGs platforms using positron emission tomography for diagnostic purposes. Theranostic platform Imaging agent Therapeutic agent Application References Thermo- responsive alginate NG co-loaded with Au NPs and cisplatin for combined cancer chemo-PTT 18 F Cisplatin CT26 tumor-bearing mice (colon adenocarcinoma) [50] PEI-based theranostic nanoplatform for glioma- targeting SPECT imaging and anticancer drug delivery 99m Tc DOX Subcutaneous tumor mouse model [48] Multifunctional nanocarrier based on triblock copolymer for simultaneous PET imaging and combination therapy Zr-89 and Cu-64 Cisplatin, Ras inhibitor farnesylthio salicylate 4T1 tumor bearing mice [51] NG, nanogel; NPs, nanoparticles; PEI, polyethylenimine; PET, positron emission tomography; PTT, photothermal therapy; SPECT, single-photon emission computed therapy. 42 Design and Applications of Theranostic Nanomedicines
- 54. iodixanol NG fortargeted X-ray CT imaging and chemotherapy of breast tumors. The NGs loaded with paclitaxel showed fast GSH-responsive drug release. In vivo studies showed that NGs prolonged the blood circulation time, enhanced drug accumulation and tumor penetration in MCF-7 breast tumor-bearing mice, allowing a marked tumor growth inhibition and survival rate of the mice. In addition, the administration of the NGs via intratumoral or intravenous injection improved CT imaging of tumors compared to iodixanol. A wide variety of nanoparticulate contrast agents including gold NPs, bis- muth sulfide NPs and ytterbium-based NPs have been explored for CT imaging [56]. A gold NP-loaded g-polyglutamic acid NG for tumor CT imaging was developed by Zhouetal. [56].The NGs demonstratedexcellent propertiesfor application as aneffective contrast agent for CT imaging in vitro and in vivo. 2.4.7 Multimodal imaging In theranostics field, the development of multifunctional NGs systems that combines different imaging modalities in a single platform have become a novel strategy used to improve the sensitivity and detection limits of clinical diagnostics [23]. This strategy takes advantage from the best attributes of each imaging agent and through their com- bination allows the developing of novel systems with enhanced properties for diag- nostic functions. Several NGs designs using multiple imaging modalities have been reported in the literature with promising results (Table 2.4). PTT employs the heat energy converted from NIR light to kill cancerous cells. The NIR region is divided into two windows, the NIR-I ranging from 700 to 950 nm and the NIR-II from 1000 to 1700 nm [66]. The light in the NIR-II window exhibits high maximum permissible exposure and deep tissue penetration than the light from the NIR-I window [67]. Therefore, PTT using the NIR-II window is preferable for the treatments. The appli- cation of MRI as diagnostic function possesses some drawbacks regarding its poor sensi- tivity that limits precision in diagnostics. Therefore, the incorporation of a second imaging modality such as PAI that combines optical and USI properties results an excellent alter- nativeto improvethe precisionof tumor imaging. In addition,most of photothermal agents can also be used for PAI. Zhang et al. [57] prepared a Gd/CuS-loaded functional NG for MR and PAI-guided tumor-targeted PTT (Fig. 2.7). The NGs were prepared by inverse emulsion and their surface was functionalized with Gd(III) chelates, targeting ligand folic acid (FA) through a polyethylene glycol (PEG) spacer and 1,3-propane-sultone. The func- tionalized NGs (Gd/CuS@PEI-FA-PS NGs) showed excellent NIR-II absorption, photo- thermal conversion efficiency, and folic acid-mediated targeting specificity to cancer cells overexpressing FA receptor. The dual-mode imaging of the NGs was assessed in vivo with a transplanted KB tumor model observingtheir capability for MR/PA dual-mode imaging- guided targeted PTT under light irradiation. Moreover, the results demonstrated the effi- cacy of the PTT of the system as evidenced by the complete tumor eradication in the group treated with the NGs after 24 days of photothermal treatment. Although PA/NIR-II dual mode imaging provides high sensitivity and good resolution morphological structure, the anatomic information provided is limited [68]. In order to avoid this limitation, Hu etal.[60]incorporatedMRIasathirdimagingtechniqueintoanNGsystem.Theydesigned a water-soluble Gd-chelated conjugated polymer-based theranostic nanomedicine (PFTQ- PEG-Gd NPs) for in vivo tri-mode PA/MR/NIR-II imaging-guided tumor PTT. The Theranostic nanogels: design and applications 43
- 55. Random documents withunrelated content Scribd suggests to you:
- 56. my fault. Well,I speak to you often enough about them. Pascuala and Mercedes! If you don’t go, I shall.” “But, mater terribilis, when I put my foot in that reception room, I get so sleepy that I can do nothing but yawn!” “Well, they are a pair of saints.” “Amen; I don’t dispute their sanctity; I am only saying that they are very tiresome and that they never stop talking. They keep up a duet like the Germans in La Diva. ‘Rogelio, how is mamma?’ ‘And how are you getting on with your studies?’ ” And he imitated the husky voice and Malagan accent of the old maids. “What nonsense you talk,” said Señora de Pardiñas, repressing a smile, “I don’t know why Pascuala and Mercedes should make you sleepy.” “Unfathomable mysteries of the human heart. Profound arcana. In that dimora casta e pura a fatal narcotic pervades the atmosphere.” “Humbug!” During this skirmish between mother and son the girl stood waiting, motionless, with her eyes fixed upon the ground. Doña Aurora, at last remembering her presence, turned toward her: “Excuse me, child; this letter says that you will tell me what you have come to see me about. Will you come upstairs?” “No, Señora. Don’t put yourself to any trouble on my account. Here will do just as well.” “Well, let me hear. Is it some favor you wish to ask of me?” “Favor? No, Señora. I would like to enter into service in your house—or in the house of some other Galician family,” she added, after a pause. Doña Aurora looked fixedly at the petitioner and fancied she reddened slightly under her gaze. “You—were not contented at the Señoritas de Romera’s, then?” “Yes, Señora, I was contented enough—and I think they were pleased with me, too. You can see that from the letter they gave me. As far as the Señoritas are concerned I would be in glory, for they are as good as they can be, not belittling others. God grant them every prosperity! Only that sometimes—there are good people that one doesn’t find one’s self at home with. Those ladies are from Malaga, in the Andalusian country, and they have customs and dishes that I don’t understand. Even their way of talking
- 57. is strange tome. When they tell me to do a thing and I don’t understand, I feel as if I had heard my death sentence. And, then, Señora, the truth before all—not to be among people of one’s own country, never to hear it mentioned, even, makes one’s heart very sad. For the half of the wages and with double the work I would rather serve a person from my own place.” All this she said with an air of so much sincerity that Doña Aurora’s good-will toward her increased, prepossessed in her favor as she already was by the respectable and decorous bearing of the girl, so different from the bold manners of the Madrid Menegildas. Only there was something in the girl’s story that was not altogether clear to her. There must be some mystery in all this. Before the door the driver was smoking his cigarette, while the hack, with drooping head and projecting lower lip, was dreaming of abundant fodder and delightful meadows. “Child,” said Señora Pardiñas. “I am going to sit down in the carriage. As I am not as young as you are I feel tired standing, and my legs are bending under me. If you don’t want to go upstairs, come over to the carriage with me.” The little Galician helped Doña Aurora to settle herself in the vehicle, and the latter when she was seated said: “Tell me, if you were so greatly attached to your country how was it that you came here?” Ah, this time there was not the slightest doubt of it; it was a blush, and a vivid blush, that dyed the girl’s cheeks. And when she answered one must be deaf, and very deaf, not to perceive that she stammered, especially at the first words. “Sometimes—one has—to do what one’s heart least prompts one to do, Señora. We are children of fate. I was brought up by my uncle, the parish priest of Vimieiro. It was the will of God to take him to himself and I was left without a protector. To get one’s bread one must work. I was a queen in my own house; now I am a servant. God be praised, and may we never lose the power of our hands or our health.” “Why did you not go out to service there?” persisted Señora Pardiñas, who had a keener scent than a bloodhound where a secret was concerned. And that the secret was there she could not doubt on seeing that it was not now a blush but a hot flame that passed over Esclavita’s face.
- 58. “I—I couldn’t finda place,” she answered, in choking accents. “And then, as everybody there knows me, I was ashamed.” Doña Aurora Pardiñas reflected for some two minutes, and speaking gently to soften the harshness of the words: “Let us see,” she said. “You can refer only to the Señoritas de Romera who—knew nothing about you before you went to their house. Isn’t it so? It would be well, then,—you will see that yourself,—if you could find some one here who knew you at home who would recommend you.” The girl hesitated for an instant, and then said: “The Señorito Gabriel Pardo de la Lage and his sister know who I am.” “Rita Pardo? The wife of the engineer? I am very well acquainted with her. And you say that she knows you?” The girl answered by raising her hand and shrugging her shoulders as much as to say, “Why, ever since I was born!” “Well, child,” rejoined Señora Pardiñas, frankly, “I am sorry that you should leave the Romeras. You could not find a better house or better ladies.” “I do not deny that,” replied Esclavita with greater emphasis than before, if possible; “only that I have told you the truth, Señora, as if I were talking to my dead mother or to the confessor. I was seized with homesickness, and if I hadn’t left them I think I should have lost my reason or have gone straight to my grave. I couldn’t eat. I would go off by myself to a corner to think. I grew paler and paler every day, and so thin that my clothes hung loose on me. At night I had fits of choking, as if some one was tightening a rope about my neck. But in spite of all that I was loth to say anything to the Señoritas. They saw it themselves, though, and they were the first to advise me, if I did not go back home, to look for a place with some family from there! ‘Child, you are so altered that you don’t look like the same person,’ were the very words they used.” As she said this, Esclavita’s chin trembled like a child’s when it is making an effort to keep from bursting into sobs. Her eyes could not be seen, as she had cast them down, according to her wont. “Calm yourself,” Señora Pardiñas said kindly. She was beginning to conceive an irresistible sympathy for this girl, whose bearing was so modest and whose heart was apparently so tender. How different she was from the
- 59. impudent servants ofMadrid, the gadabouts of the suburbs, shameless termagants who could not stay in any decent house. It was not two hours ago that Pepa, the house-maid, for a mere nothing had thrown aside all decency and scolded like a fishwoman. This little Galician might have had —well, some slip—for the reasons she gave for leaving her native place did not seem all clear; but her whole appearance was so—well, so like that of an honest woman—God alone knew how the poor thing had been tempted. “‘See,’ she said, putting her head out of the carriage door.” “See,” she said, putting her head out of the carriage door, “for the present I cannot give you a decided answer as to whether I will take you or not. Come to the house to see me to-morrow morning about this time. I should be glad to—but I must think the matter over. If I should not be able to take you myself, I will look for a place for you with some other Galician family. Tell me your conditions, in case any one else should want to know.” Esclavita, meantime, stood rolling an end of her black silk handerchief between her thumb and forefinger. “May God reward you!” she answered. “As for the wages, a dollar more or a dollar less makes no difference to me. Work does not frighten me. I would not engage as a cook, for I don’t know how to make those fine dishes that are the fashion now. I understand simple dishes like those of my native
- 60. place. In everythingelse I think I could give satisfaction—in the cleaning, the mending, and the ironing. All I ask is that in the family you look for there should not be—well, men, who——” “I understand, I understand,” interrupted Doña Aurora. And she added jestingly, “But in that case, tell me why you want to come to my house. Haven’t you seen that there is a man in it?” And she pointed to Rogelio who, relieved from his embarrassment by his mother’s presence, stood leaning against the carriage door, looking at the girl. Esclavita followed the direction of Señora Pardiñas’ hand; for the first time her eyes, green, changeful, sincere, rested on the student. After a pause she said with a smile: “Is that young gentleman your son? May God spare him to you for many years. That isn’t the kind of man I mean, he is only a boy.” Rogelio changed countenance as if he had received the most outrageous insult. He tried to disguise his annoyance by a laugh, but the laugh died away in his throat. It must be confessed that he even felt his eyes fill with tears of vexation. It was one of those moments of insensate and profound rage which must come at one time or another to the man whose childhood has been unduly prolonged; moments in which he desires, as if it were the highest good, to possess the bitter treasure of experience—sorrows, disappointments, trials, struggles, sickness, gray hairs, wrinkles, calamities, betrayal of friendship and of love—all, all, so that he may hear the supreme word, so that he may taste the fruit of good and evil, the immortal apple, golden on the one side, blood-red on the other. All, so that he may fulfill the destiny of humanity, all, so that he may pass through the cycle of life.
- 61. VI. When the driverwhipped up his horse, Señora Pardiñas called out to her son, who was on the box: “Give him Rita Pardo’s direction.” Rogelio obeyed; but when they reached the house in the dingy Calle del Pez, in which the engineer’s wife lived, he jumped down and opening the carnage door, said to his mother: “I won’t go in. To make your inquiries you have no need of me.” “And where are you going now?” “Oh, to take a turn,” responded the student, indifferently, with a farewell gesture of the hand which betrayed the impatience of the boy growing into manhood to assert his manly independence, something like the nervous fluttering of the wings of the bird when his cage door is opened to him. Without further explanation he drew his cloak more closely about him and disappeared around the nearest corner. His mother followed him with her eyes as long as he remained in sight, then she sighed to herself and half smiled. “It must come some day,” she thought. “He is at an age when the reins cannot be held too tightly. Of course, the poor boy does not impose upon me, that is only to show his independence; he will look in at a few shop-windows, buy half-a-dozen periodicals, and take a turn or two with any friend he chances to meet, and then go to the apothecary’s. If I could only see him strong, robust, burly—there are boys at his age that are perfect giants that have a beard like a forest. He is so delicate, and so puny! Our Lady of Succor, bring me safely through!” These maternal anxieties had calmed down by the time Señora Pardiñas, releasing her grasp on the banister of the stairs, had rung the bell of Rita Pardo’s apartment—a third floor with the pretensions of a first. The door was opened by a girl of eleven or twelve, pale, black-eyed, with her hair in disorder, her dress in still greater disorder, who as soon as she saw the visitor ran away, crying: “Mamma! Mamma! Señora de Pardiñas!” “Show her into the parlor; I will come directly,” answered a woman’s voice from the inner regions of kitchen or pantry. Doña Aurora, without
- 62. waiting for thepermission, was already entering the parlor, a perfect type of middle-class vulgarity, full of showy objects, and without a single solid or artistic piece of furniture. There were three or four chairs covered with plush of various colors, an étagère on which were some cast-metal statuettes; several trumpery ornaments and silver articles which were there only because they were silver; two oil-paintings in oval frames, portraits of the master and the mistress of the house, dressed in their Sunday finery; on the floor was a moquette carpet, badly swept. It was evident that the parlor was seldom cleaned or aired, and the carpet gave unmistakable indications of the presence of children in the house. At the end of ten minutes, Rita Pardo, the engineer’s wife, made her appearance. She came in fastening the last button of a morning gown, too fine for the occasion, of pale blue satin trimmed with cream-colored lace, which she had put on without changing her undergarments soiled in her household tasks. She had powdered her face, and put on her bracelets. Although she was no longer young and her figure had lost its trimness, neither maternity nor time had been able to dim her piquant beauty, but the coquette whom we remember laying her snares for her cousin, the Marquis of Ulloa, had been transformed into a circumspect matron, with that veneering of decorum under which only the keen eye of the student of human nature could discover the real woman, such as she was, and would ever remain; for the real man and the real woman, however they may disguise themselves, do not change. She greeted Señora de Pardiñas cordially, with her usual, “What a pleasure to see you, Aurora! Heavens! in this life of Madrid months may pass without seeing one’s friends or knowing whether they are living or dead. You have caught me like a fright. The mornings are terrible—they slip away in listening to idle chatter and sending and receiving messages. How sorry Eugenio will be——” No sooner had Doña Aurora broached the subject of her visit than Rita Pardo suspended the flow of her talk and waited to hear further, with evident curiosity depicted in her voluptuous black eyes, and on her hard, fresh mouth. A series of ambiguous gestures and malicious little laughs was the prelude to the following commentary: “What do you tell me? What do you tell me? Esclavita Lamas. The rector of Vimieiro’s Esclavita Lamas! Ta, ta, ta, ta, ta! And how has Esclavita Lamas happened to come across you?—Isn’t she a girl with auburn hair?”
- 63. “I don’t knowwhether her hair is auburn or not. She wears a shawl over her head. She is in deep mourning and looks very neat. Her appearance is greatly in her favor.” “Well, well, well! Esclavita Lamas! Who would have thought it! Yes, she is, as we say in our part of the country, very demure, very mannerly; she talks so soft and low that at times you can scarcely hear her. She smells a hundred leagues off of the sacristy and of incense. A little saint!” “Who would have thought it!” Doña Aurora was more discouraged than was reasonable by this preamble; she resolved, however, to disguise her feelings and to find out the truth, the whole truth, even though it should grieve her to the heart to hear any ill of the girl, in whom she was deeply interested. “So that you know her very well?” she said. “Heavens! As well as I know my own fingers. Indeed I know her! Lamas Tarrío was a great friend of the family even while he was in the other parish in the mountains before papa presented him for Vimieiro. He always lived in our house, and he was very fond of making presents. What lard, what cheese, what eggs at Easter and what capons at Christmas he used to give us! Papa thought a great deal of him, for in the mountains he took charge of the collecting of the rents. In short, he was devoted to us. He was indebted to papa, too, for a great many favors, important favors, Doña Aurora.” “Well, what I want to know is what relates to the girl. If her antecedents are good, and I can admit her into my house, I shall be glad of it. I am not satisfied with Pepa, and I have taken a liking to this girl.”
- 64. Rita Pardo smiledmaliciously, as she smoothed out the lace of her left sleeve, a little crumpled with use. She arched her eyebrows, and made a grimace difficult of interpretation. “Um! Good antecedents may mean much or little, as you know. What is good for one is only middling for another. In that matter, some people are more particular than others. If the girl pleases you so much——” “No, not so fast!” exclaimed Señora de Pardiñas, alarmed. “For me good antecedents are good antecedents, neither more nor less. Be frank and tell me all you know, for that is what I have come for; and now with the thorn of suspicion you have planted in my mind, I would not take the girl, not if she were crowned with glory, unless you explain to me——” Rita smoothed out her lace again, and gave a little sigh of embarrassment as she answered: “Aurora, there are certain things that, no matter how public they may be, one cannot have it on one’s conscience to reveal them. You know nothing about the matter, eh? Then it would be very ugly on my part to enlighten you. So much the better if it has not reached your ears; it is an advantage for Esclavita. And you can take her without any hesitation; I am certain she will turn out an excellent servant.” “You are jesting, Rita,” said Señora de Pardiñas, letting her growing irritation get the better of her, “You envelop the affair in mystery, you make a mountain out of it, and then you tell me that I may take Esclavita. No, child; in my house people are not received in that way, without knowing anything about them. Explain what you mean——” When the interview had reached this point Rita assumed a manner that was almost discourteous; she threw herself back, her nostrils dilated, her bosom swelled, and she began to excuse herself from answering with an air of offended dignity and wounded modesty. When, after exhausting all her arguments, Doña Aurora obtained for her sole response, “I am very sorry, but it is impossible,” she rose, without troubling herself to conceal the annoyance this impertinent affectation of modesty had given her. She was just saying angrily, “Excuse my having come to trouble you,” when after a loud ring at the bell, followed by exclamations in a childish voice in the hall, the eldest girl—the twelve-year- old madcap, rushed joyfully into the parlor, crying: “Mamma! mamma! Uncle Gabriel!”
- 65. Then, the widowPardiñas, with sudden inspiration, planted her feet firmly on the floor, saying to herself: “Now I shall have my revenge. Now you shall see, hypocritical cat, impostor, humbug!”
- 66. VII. The commandant, dressedin the costume of a peasant, unceremoniously entered the room with his niece, who was the apple of his eye, his arm encircling her waist as if he was going to dance a waltz with her. In the salutation he exchanged with his sister, however, Doña Aurora could detect a shade of coldness, not far removed from dislike, a feeling which can sometimes be dissimulated where strangers are concerned, but never where its object is a member of one’s family. After the customary salutations and compliments, Señora de Pardiñas, who did not belie her race so far as wiliness and obstinacy were concerned, said tentatively: “Well, I will leave you now. After all, I did not find out what I had come to learn, and consequently—— Your sister is very reserved, Señor de Pardo.” “Upon my faith, I have never thought so,” answered the artilleryman bluntly, almost rudely. “Well, every one speaks of the fair according to the bargain he has made. With me she has shown herself extraordinarily reticent.” And without heeding the gesture or the glance of Rita, she continued undaunted: “For the last quarter of an hour I have been asking information from her in vain about a young countrywoman of ours, Esclavita Lamas, the niece of the rector of Vimieiro.” Pardo listened like one in whose memory some vague recollection has been awakened. “Stay—let me think—Vimieiro—Lamas—Lamas Tarrío. He was an intimate friend of papa’s. Rita knows all about him; she has the whole story at her fingers’ ends.—What objection have you to tell it to Doña Aurora?” A caricaturist desiring to represent bourgeois dignity in its most exaggerated form might have copied with exactness the features and expression of Rita as, arching her brows and pointing to her eldest daughter leaning against the commandant’s knees, she exclaimed impressively: “The child!” “Well, what of the child?” responded Don Gabriel, imitating his sister’s tragic tone. “Is it one of those shocking things that innocent ears must not
- 67. hear—that the cathas had kittens, for instance?” “Gabriel, you are dreadful,” groaned Rita, casting up her beautiful southern eyes. “When one is killing one’s self, trying to make your nieces what they ought to be in society, you must do your best to—there is no use in trying to struggle against people’s dispositions.” “Well,” insisted the obstinate Doña Aurora, “I come back to my complaint. Rita, don’t say that it was for the child’s sake that you refused to give me the information I asked. The child was not present, and even if she had been, by sending her out of the room——” “Well, what of the child?” “Which is what I am going to do now. Eugenita, child, go practice your Concone.” The girl left the room, much against her will, casting on her uncle, as she went, a couple of affectionate farewell glances; but no scale or study was heard to tell that she had shut herself in the musical torture-chamber in which our young ladies, worthy of a better fate, are condemned to dislocate their fingers daily. “You shall hear,” said Doña Aurora, emphatically, “now that we can speak freely. The question is that that girl, Esclavita Lamas, wants to enter my service; and that I, for my part, am greatly pleased with what I have seen of her. But I know nothing about her past, nor why she left her native place. There seems something odd in the whole affair. Your sister knows the story, and neither for God’s sake nor the saints’ will she tell it to me. There
- 68. you have thecause of our dispute. It was beginning to grow serious when you came in.” “The story,” said Gabriel, nervously wiping his gold-rimmed spectacles, and putting them on again carefully. “Wait a moment, Señora; for if my treacherous memory does not deceive me—Rita, is not that the Father Lamas who took a poor girl off the street into his house for charity? Tell the truth, or I shall write this very day to Galicia to inquire.” “Heavens! What notions you have! You are growing more unbearable every day—Was I not going to tell you the truth? Yes, that was the Lamas, and since you insist upon opening his grave, and dragging him out to public shame, do it you, for I don’t want to have such a thing on my conscience.” “It should weigh more heavily upon your conscience,” replied Gabriel, with vehemence, “to try to prevent the girl getting her place on account of the sins of others. Now I can tell you the whole story, Doña Aurora, by an end I have unwound the skein; it is the same with stories as with an old tune —if one remembers the first bar, one can sing the whole of it through without a mistake. And I can tell you that it is a novel, a real novel.” “It may seem so to you,” said Rita, venomously, pulling the lace of her sleeves again. “As for me—there are certain things—— Well, I wash my hands of it.” Doña Aurora concealed the satisfaction her victory gave her, but, a woman after all, she said to herself, casting a side glance at Rita: “I’ve got the best of you, hypocrite!” “You shall hear,” began the commandant. “This Father Lamas was a simple-minded man, illiterate as all the rural clergy were at that time,—now they are much more enlightened,—and not over-intelligent; but he performed all his parochial duties faithfully, and if he committed faults he succeeded in hiding them. If you cannot be chaste, be cautious, as the saying is. Well, one night there came to the door of the rectory a girl, about tea years old, an orphan, who lived upon charity; in one house they gave her a piece of corn bread, in another a bundle of corn leaves to sleep upon, here a ragged shawl, there a pair of old shoes. In this way the wretched girl managed to live. The rector took pity upon her and said to her: ‘Stay here; you can learn housework; you will have clothes to wear, a bed to sleep in, and good hot soup to nourish you.’And so it was decided—the girl stayed.” “The girl was Esclavita?”
- 69. “No, Señora, noSeñora. Wait a while. The girl turned out bright and capable; she put away from her her melancholy, as they say in our country, and she even grew rosy and handsome. And—” here the voice of the commandant took a sarcastic tone—“when the flower of maidenhood bloomed—” “Oh, Gabriel,” remonstrated Rita, “certain things should be spoken of in a different way. There is no need of entering into details that——” “Bah!” said Doña Aurora. “We are all of us married and I am an old woman. We know all about it and are not to be so easily shocked as that comes to, my dear. Go on. What came afterward?” “Afterward came Esclavita.” Although Señora Pardiñas had affirmed that she knew all about it, this piece of information, given thus suddenly, almost made her jump in her chair. “Ah!” she exclaimed, and then looked very thoughtful. “That is why the poor girl—well, and afterward?” “Afterward,” cried Rita impetuously, unable to keep silent any longer, “papa had the greatest difficulty to pacify Señor Cuesta, the Cardinal Archbishop. As the Archbishop himself was so virtuous he maintained strict discipline and permitted no misconduct. If it were not for all papa’s efforts with his eminence, to-day one entreaty and to-morrow another, Lamas Tarrío would have been deprived of his license and would have been left to rot in the ecclesiastical prison. For it is one thing for a priest to commit a fault that no one knows anything about, and another to scandalize his parishioners, bringing up the child in his own house, outraging public opinion, petting and indulging her——” “My father,” said Gabriel, interrupting his sister, “with one hand smoothed down the Archbishop and with the other hammered away at the sinner. By dint of exhortations he succeeded in having the siren sent away from the rectory; but Lamas continued to see her. At last papa took a firm stand and prevailed on him to allow the mother to be sent to Montevideo, on condition that he was permitted to keep the child.” “Yes,” again interposed Rita, “a fine remedy that was, worse than the disease. The man became wilder and more reckless than he had been before. He spent night after night without closing an eye, crying and screaming. He had a rush of blood to the head—he was in our house at the time—so that
- 70. they were obligedto apply more than forty leeches to him at once, and the blood that came was as black as pitch. We thought he would go mad; he would go about the corridors tearing his hair, calling on the woman’s name with maudlin expressions of endearment.” As Rita said this her brother observed that the curtains of the adjoining room moved as if they had been stirred by a breath of hoydenish curiosity, and the outlines of an inquisitive little nose were vaguely defined against them. “The outlines of an inquisitive little nose were vaguely defined against them.” “See,” he said, “now it is you who are getting beyond your depth. All that has nothing whatever to do with the case. Let us end the story at once, and let me tell it in my own way. Poor Lamas became so ill that the Archbishop himself was sorry for him, and sent for him to cheer him and inspire him with thoughts of penitence. And in effect, in process of time he grew calmer and even behaved himself very well afterward. The only fault to be found with him was that he brought up the child with extraordinary indulgence; but as the feelings of a father, even when they contravene both human and divine laws, have something sacred, people shut their eyes to this. He introduced the girl as his niece. As such children do not inherit, the priest saved up money, ounce upon ounce, which he put into Esclavita’s own hand; but the girl, who had turned out very discreet and very devout,
- 71. and, in additionto that, very unselfish, when Lamas died, gave all this money, in gold as she had received it, for masses and prayers for the soul of the sinner. This act alone will give you an idea of the girl’s character. There are not many girls who would do so much even if they had been born in a better station and in a more orthodox manner.” “As my brother is of a romantic turn he sees things in that way,” interposed Rita. “Señora de Pardiñas, I give you my word as a gentleman that I neither add nor diminish. That girl, in my opinion, would be capable of going bare- footed on a pilgrimage to any part of the world in order to get the soul of the rector of Vimieiro out of purgatory.” “And well he would need it,” said Rita, “and her mother too, who, by all accounts, does not lead the life of a saint over there in America.” “Good Heavens! How merciless you women can be, who have never had to suffer for the want of consideration or of bread,” exclaimed Pardo, now really angry. “I do not err on the side of philanthropy, but there are certain things that I cannot understand in people who make a boast of being good Christians and who go to mass and say their prayers. Fine prayers those are! Is that what you understand by charity? Well, my dear, I declare that Esclavita is worth more than——” Fortunately he restrained himself in time and ended: “Than some other people. How is she to blame for her parents’ faults? Tell me that! And she is expiating them as if she had committed them. She even left her native place, it seems, so as not to be where people know and remember and discuss——” “I would swear the same thing,” asserted Doña Aurora warmly. “Now I know why it was that she became so confused when she was asked certain questions. I am of the same opinion as you, Pardo, that she is good, that she has noble sentiments, and that those traits do her honor.” “Yes, be guided by my brother, admit her into your house,” exclaimed Rita, with a spiteful and insolent laugh. “For giving advice, Gabriel has a special gift. I tremble when he and my husband get together. If Eugenio were to be led by him we should be living on charity. Take that girl on your hands, and you will see how it will end. Then you will say, ‘Rita Pardo was right after all.’ ” Señora Pardiñas thought within herself:
- 72. “I will takeher if only to spite you, hypocrite, impostor. I have taken your measure, now.” When Gabriel was going out, he found his eldest niece waiting for him in the reception room. He caught her by the waist, and lifting her up to a level with his mouth, whispered in her ear: “Good little girls, if they want Uncle Gabriel to love them, must not go peeping and spying and hiding themselves behind portières. They must obey mamma because she is mamma, and she will not tell them to do anything wrong. Take care and don’t bite, little lizard. Good little girls—are good. Ah-h-h! my cravat!” “He caught her up by the waist.” “Uncle Gabriel, will you take me with you?” coaxed the little madcap. “With you, yes; with you, no; with you, yes, I will go. Come, take me with you!”
- 73. “The commandant threwa kiss to the girl, which she promptly returned.” “To Leganes it is that I will take you. Be good now! Study your French lesson! Comb that mane of yours! Run into the kitchen to see what the girl is about there! Papa likes his roast beef well done! See to papa’s roast beef!” As he crossed the threshold the commandant threw a kiss to the girl, which she promptly returned.
- 74. VIII. Doña Aurora wasin the habit of taking her son his chocolate every morning before he was out of bed, for, old-fashioned in many other respects, the household was old-fashioned also in the matter of early rising. Those were delightful moments for the doting mother. The boy, as she called him, felt on awakening that causeless joy peculiar to the springtime of life, that season when each new day seems to come fresh from the hands of time, golden and beautiful, and embellished with delights, before painful memories have begun to weigh down the fluttering wings of hope. Rogelio, who in the afternoon suffered from occasional fits of nervous depression, in the morning was as gay and sprightly as a bird. Even his chatter resembled the chirping of birds or the cooing of infants when they open their eyes in the morning. His mother, after removing the articles of clothing and the books lying about, would seat herself at his bed- side and hold the tray, so that the chocolate might not spill as the boy dipped the golden biscuits into it, while a glass of pure fresh milk stood beside it waiting its turn. “His mother ... would seat herself at his bed-side and hold the tray.”{102} And what anxiety and trouble this glass of milk cost Doña Aurora! She knew more on the subject than the entire municipal board of chemists; without analysis or instruments or other nonsense of the kind, she could distinguish, simply by looking at it, by its color and its odor, every grade and quality of milk that is consumed in Madrid. For her hopes of seeing
- 75. Rogelio grow robustwere all centered in that glass of milk drank before going to college, and in the beefsteak eaten after returning from it. While he was taking his chocolate, it was that all the events of the preceding day were discussed, the amusing skirmishes between Nuño Rasura and Lain Calvo, the college jokes, the latest crime, last night’s fire, together with all the trifling incidents of that home so truly peaceful like many another in the capital, notwithstanding the provincial superstition that Madrid is a perpetual whirlpool or vortex, Rogelio’s first words on the morning following the day of the Galician’s application were to ask his mother with ill-disguised interest: “Well, what did they tell you about the fair maid—of all work?” There was nothing strange or out of the way in his asking this question, and yet Doña Aurora was somewhat embarrassed by it, and hesitated whether she should tell him what she had heard or keep it to herself. No, it would be more prudent to say nothing about it. It was a serious matter, and if Rogelio should be wanting in discretion—it was necessary to proceed with caution. “See, little mouse, in the first place I must tell you that I have dismissed Pepa.” “Hello! Is a change of ministry to take place here without my being consulted in the matter?” “You shall hear! She was getting to be very conceited, very fond of answering back. So I handed her her wages. I will bear anything from them but answering back. I suppose there was a lover in the business or she would not——. To tell the truth I am tired of these Madrid servants, they are so upsetting and unbearable with their airs and assurance. I prefer a modest, docile girl. With a civil word you can conquer me, I can’t help it. If you were to see that Pepa, as stubborn as a mule and as wild as a mountain rabbit. Ah, I can’t believe that she is gone!” “Mater, enough of prolegomena,” exclaimed the boy, dipping the end of his biscuit into the milk. “All this means that you are going to take the black-robed Unknown. She found her way straight into your heart through your eyes. We all have our weaknesses.” “Don’t be foolish. What I want is that things should run smoothly in the house. That is a deserving girl. When I say so——”
- 76. Welcome to ourwebsite – the perfect destination for book lovers and knowledge seekers. We believe that every book holds a new world, offering opportunities for learning, discovery, and personal growth. That’s why we are dedicated to bringing you a diverse collection of books, ranging from classic literature and specialized publications to self-development guides and children's books. More than just a book-buying platform, we strive to be a bridge connecting you with timeless cultural and intellectual values. With an elegant, user-friendly interface and a smart search system, you can quickly find the books that best suit your interests. Additionally, our special promotions and home delivery services help you save time and fully enjoy the joy of reading. Join us on a journey of knowledge exploration, passion nurturing, and personal growth every day! ebookbell.com