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Dialysis
This document provides an overview of dialysis, including its principles and applications. Dialysis is the process of separating molecules through a semi-permeable membrane based on differences in diffusion rates. It works by restricting the passage of larger molecules in a sample solution while allowing smaller molecules to diffuse through the membrane into a buffer solution. Regenerated cellulose membranes of varying molecular weight cut-off are commonly used. Dialysis has many applications, including hemodialysis to remove waste from blood, microdialysis for medical analysis, and electrodialysis to transport ions between solutions.
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Dialysis
- 1. Dialysis Submitted by :D.Sairam Course Instructor : Dr. Subhabrata Kar Course : Bioanalytical and Instrumentation-I Course Code: BSBT 202 Presentation Code: U2P2
- 2. Overview Introduction Principleof Dialysis MWCO Preparation of Dialysis membranes Characteristics of Regenerated Cellulose Membrane Applications of Dialysis References
- 3. Introduction • Dialysis comesfrom two Greek words namely ‘Dia” and “Lysis” meaning splitting or separating materials through a membrane • Earliest Dialysis was carried out of Crystalloids using Albumin coated parchments. • Today Dialysis ( reference to medical dialysis) has become a life saving technique that is widely used all over the world. Source: Wikimedia
- 4. • Dialysis isthe process of separating molecules in solution by the difference in their rates of diffusion through a semipermeable membrane. • In dialysis, a sample and a buffer solution (called the dialysate) are separated by a semi-permeable membrane that causes different diffusion rates, thereby permitting the separation of molecules in both the sample and dialysate. • It is due to the pore size of the membrane that large molecules in the sample cannot pass through the membrane, thereby restricting their diffusion from the sample chamber. • Once equilibrium is reached, the final concentration of molecules is dependent on the volumes of the solutions involved, and if the equilibrated dialysate is replaced (or exchanged) with fresh dialysate (see procedure below), diffusion will further reduce the concentration of the small molecules in the sample. • If the equilibrated dialysate is replaced (or exchanged) with fresh dialysate (see procedure below), diffusion will further reduce the concentration of the small molecules in the sample. Principle of Dialysis
- 5. • The Molecular-Weightcut-off (MWCO) parameters characterize Dialysis membranes. • Membranes with MWCOs ranging from1-100,000 kDa are commercially available, membranes with MWCOs near 10 kDa are most commonly used. • MWCO refers to the smallest average molecular mass of a standard molecule that will not effectively diffuse across the membrane during extended dialysis. • Molecules near the MMCO value will diffuse very slowly so this shows the importance of choosing an appropriate membrane. • Ideally a molecule must be at least 20- to 50-times smaller than the MWCO rating of a membrane to allow smooth diffusion. • Dialysis membranes for laboratory use are typically made of a film of regenerated cellulose or cellulose esters MWCO
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- 7. Preparation of DialysisMembrane • Membranes ( used in Laboratory Dialysis) are generally are made up of regenerated Cellulose. • Glycerol is frequently added as a humectant to prevent cracking during drying and to help maintain desired pore structure • Pores range from 15-50 Angstroms for 3.5K, 7K and 10K MWCO membranes • Regenerated cellulose is hydrophilic and easily saturated in buffer to provide a homogeneous medium for dialysis in aqueous solutes • Membrane contaminants include sulfur compounds (0.01-0.3%), heavy metals (trace) and glycerol (0-21%). • Most of these small compounds diffuse out of the membrane during the dialysis process> Solution: pre-dialysis
- 8. Characteristics of RegeneratedCellulose membrane • It is an economical material that is best suited for applications where particles ( significantly large) are separated on the basis of their size. • It is chemically stable in most conditions. • It can be used with dilute strong acids and bases, concentrated weak acids and bases. • It can tolerate pH 2 - 12 and temperatures 4 - 121 °C. • However, Biotech Grade Dialysis Membranes are preferred for processes that involve higher membrane purity and better selectivity
- 9. Applications of Dialysis •The applications of Dialysis are far and varied. The following is a compilation of a few of them: • Haemodialysis: Removal of salts, creatinine from blood in case of Renal failure. • Micro dialysis: Removal of extracellular fluid, hormones for analysis and to determine their concentrations in the body. • Electrodialysis (ED): It is used to transport salt ions from one solution through ion-exchange membranes to another solution under the influence of an applied electric potential difference. • Peritoneal Dialysis (PD): It uses the patient's peritoneum (in the abdomen ) as a membrane across which fluids and dissolved substances (urea, glucose, albumin and molecules) are exchanged from the blood.
- 10. Peritoneal Dialysis Electro Dialysis Source:National Kidney Foundation, USA
- 11. Reference • https://www.kidney.org/atoz/content/dialysisinfo • http://renux.dmed.ed.ac.uk/EdREN/Unitbits/historyweb/HDWorld. html • http://www.spectrumlabs.com/dialysis/biotech.html •http://www.doctorslounge.com/nephrology/articles/dialysis_adequ acy/adeq3.htm • http://en.wikibooks.org/wiki/Structural_Biochemistry/Proteins/Pur ification/Dialysis • http://www.davita.com/kidney-disease/dialysis/motivational/the- history-of-dialysis/e/197