Synthesis and Characterization of Biocompatible Mixed Matrix Membranes for Hemodialysis Application

Abstract

Hemodialysis is an example of laboratory technique that separates solute molecules on the basis of their molecular weights (sizes) via a semi permeable membrane. It is an extensively used extracorporeal technique for the treatment of end stage renal disease patients. The main objective of this study is to prepare a polymeric membrane that has optimized morphology,diffusive permeability and biocompatibility for the hemodialysis process. For this purpose a mixed matrix membrane is prepared in which cellulose acetate (CA) acts as a base polymer. Cellulose acetate is chosen because of its easy availability, cost effectiveness and biocompatibility. In this work, a series of asymmetric membranes have been synthesized and incorporated with various organic additives. The flat sheet membranes were prepared through phase inversion process while the hollow fibers by dry-wet jet spinning technique. Membranes morphology was studied using SEM analysis, Atomic force microscopy, Fourier Transform Infra-red Spectroscopy and Contact Angle. To check the membrane performance BSA rejection, Pure Water flux, Water content, Porosity, Urea and Creatinine clearance tests were performed. Biocompatibility tests were conducted to find the interaction of blood with the artificial membrane surface. In the first section, CA was blended with polyethyleneimine(PEI). The CA/PEI membranes were further modified with polyethylene glycol to improve the porosity of the membranes. This membrane has shown enhanced BSA retention with moderate urea rejection. Membrane showed 80% BSA rejection with 76.6 % Urea clearance. It was further studied to modify it. Overall Creatinine clearance was 20% making it less suitable for dialysis operation. To further enhance the properties of membrane evaporation rate was studied. In the second section, hollow fiber membrane was fabricated using various air gaps. Membranes have shown 90% BSA retention, Urea clearance of 90%, Creatinine clearance of 40% with the Lysosome up to 14%. Secondly the membranes were incorporated with Citric acid and Gelatin to check the biocompatibility. The Citric acid has shown less protein adsorption, platelet adhesion, thromobogensis and hemolysis ratio making it suitable for the dialysis operation. iv In conclusion, CA/PEI/PEG membrane has shown best result in hollow fiber configuration at an air gap of 10 cm. Providing new aspect in the hemodialysis domain; membrane is indigenously produced and results in clearance of small as well as middle uremic molecules. Secondly, the biocompatibility results favor its use in the place of current dialyzer membranes.