Natural Polymer based Biocompatible Hemodialysis Membrane

Abstract

With 850 million affected people globally, ESRD is expected to rank as the fifth leading cause of death globally by 2040. Of all kidney replacement therapies, hemodialysis is the most widely used kind in the world, serving approximately 2 million patients. Different synthetic polymeric membranes are used for HD treatment and natural polymer based membranes were not evaluated in hemodialysis research. Current dialysis systems frequently deal with problems like hemocompatibility and dialysis performance or vice versa and high death ratio suggests the improvement in this field. In current research work, silk fibroin (natural polymer) was extracted from silk cocoon and thin film membrane were fabricated and evaluated in hemodialysis application. Different types of membrane were cast based on formulation of variable weight percentage of pure silk (5, 7 and 9 wt.%) and blending of silk with PEG solutions. Polyethylene glycol was added to enhance the hemo-compatibility and wettability of pure silk membranes. FTIR results described that pure silk fibroin was successfully separated from silk cocoon and hydrogen bonding occurred between silk and PEG when blended together. Thermo- rheological analysis illustrates that addition of PEG to silk fibroin decreased the gelling temperature from 46C to 31C. Casting the membrane from its solution in control heating environment developed unique capillary system in all fabricated membranes as shown by FESEM analysis. Contact angle results showed that low molecular weight pure silk (5%) was highly hydrophilic (53.65) and addition of PEG further increased the hydrophilic character (54.07). Density measurements confirmed that with increasing silk weight in cast membranes density were also enhanced and all membrane did not allow the 20kDalton solute molecules to pass through them, thus can forbid the useful albumin loss during dialysis. Alamar Blue Assay and human blood plasma were used to evaluate the biocompatibility of cast membranes and cytocompatibility and blood clotting experiments illustrate that pure silk and silk-PEG membranes are non-toxic and hemocompatible. Further, the dialysis results showed the 47-49% clearance rate of urea and creatinine in a dialysis cell.