Surface modification of nylon membrane by glycidyl methacrylate graft copolymerization for antibody immobilization

Abstract

Surface of nylon membrane was modified by the graft copolymerization of glycidyl methacrylate (GMA) using persulfate and thiosulfate as redox initiator system. Effect of various reaction parameters such as initiator concentration, monomer concentration, polymerization time, and temperature on degree of grafting was also studied. Maximum grafting of 100% was achieved by using equimolar concentration (0.008M) of redox initiator and 0.5M of GMA monomer at 70°C in 60 min. Grafted nylon membranes with various graft levels of GMA were characterized by various techniques such as fourier transform infrared spectroscopy, thermo gravimetric analysis, and scanning electron microscopy. The GMA grafted nylon (NyM-g-GMA) membranes with different graft levels were evaluated as a support for immobilization of rabbit anti goat antibody (RAG IgG). Antibody (Ab) immobilized NyM-g-GMA membranes were evaluated using ELISA and Bradford protein estimation method. Nylon membrane with 60% graft level showed optimum immobilization of Ab at RAG IgG conc. of 0.625 μg/mL with low nonspecific binding. Maximum immobilization efficiency (I.E.%) of 56% was observed for membrane with 60% graft level at 50 μg/mL of RAG IgG in PBS (pH 7.4). Ab immobilized NyM-g-GMA discs were found to be stable up to 6 weeks at 4°C and 2 days at 37°C. © 2010 Wiley Periodicals, Inc.