DEVELOPMENT OF FUNCTIONAL COPOLYMER BRUSHES FOR PROBE IMMOBILIZATION IN BIOSENSING APPLICATION

This research aims to develop copolymeric platforms containing poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) for biosensing applications. The first platform was based on copolymer of poly[(propargyl methacrylate)-ran-(2-methacryloyloxyethyl phosphorylcholine)] (PPgMAMPC) which were synthesized by RAFT polymerization. Thiol-terminated PPgMAMPC (PPgMAMPC-SH) were immobilized on gold-coated surface plasmon resonance (SPR) disk by “grafting to” approach. Biotin and peptide nucleic acid (PNA) were used as model probes to study the immobilization and specific binding for antigen/antibody and PNA/DNA biosensor, respectively. Effect of copolymer composition on probe binding density, analyte detection efficiency as well as the ability to prevent non-specific adsorption was evaluated. Gold-coated SPR chip immobilized with PPgMA45MPC55-biotin exhibited the best performance in streptavidin detection in blood plasma solution with a detection limit of 0.95 nM, while the sensor platform based on Au-PPgMA65MPC35-PNA could detect the highest amount of complementary DNA with %hybridization efficiency of 71%. The second platform was based on copolymer of methacryloyl-functionalized glycoproteins (ManM-treated glycoproteins) and MPC which was developed for influenza hemagglutinin detection. ManM-treated-glycoproteins were harvested from HL-60 cells surface-modified with N-methacryloyl mannosamine (ManM). Among all methods investigated, direct immobilization of ManM-treated-glycoproteins together with MPC on gold-coated SPR substrate via thiol-ene reaction was the most effective.