CHEMICAL SURFACE MODIFICATION OF POLYIMIDE FILM FOR ENHANCED COLLAGEN IMMOBILIZATION AND CELLULAR INTERACTIONS

Different natural and synthetic polymers have been studied as an insulator and carrier for retinal prosthesis or as a scaffold for cell transplantation. The use of synthetic poly-mers outmatches natural polymers in some aspects including degradation, processability and strength. The synthetic polymers can be surface modified by proteins to promote their hydrophilicity, cell adhesion, and biocompatibility. Chemical surface modification is one of the stable means of protein immobilization in which proteins can be grafted covalently onto the surface. The generated covalent coupling protects the protein from shear stresses applied on the biomaterial and changes in pH of environment. The aim of this thesis was to modify the surface of polyimide (PI) membrane by co-valent coupling of adhesive molecule collagen IV to improve the retinal cell interaction with PI substrates. Therefore, acrylic acid graft polymerization was carried out on the plasma treated membrane and the number of carboxyl groups on the membranes was determined using Toluidine Blue O (TBO) method. Lastly, a peptide bond was pro-duced between collagen and carboxyl groups by means of carbodiimides and N-hydroxysuccinimide crosslinkers. The surface morphology and hydrophilicity of mem