Synthesis and sensor application of carboxyl-containing polymer brushes

In this work, sensor platforms based on carboxyl-containing polymer brushes have been developed. The carboxyl-containing polymer brushes, were prepared on gold-coated surface plasmon resonance (SPR) disks by two approaches (1) “grafting from” via surface-initiated atom transfer radical polymerization (SI-ATRP) and (2) “grafting to” via self-assembly of thiol-terminated polymer. The homopolymer brushes of poly(acrylic acid) (PAA) with varied graft density were obtained by SI-ATRP. The result obtained from SPR technique indicated that the graft density and swellability of the PAA brushes had significant impact on the sensing probe immobilization and analyte detectability. The sensing probes immobilized on PAA brushes not only showed the specific binding with target molecules but also maintained high resistance to non-specific protein adsorption yielding the high S/N in comparison with those immobilized on the carboxyl-terminated self-assembled monolayer surface. The copolymer brushes of poly[(methacrylic acid)-ran-(2-methacryloyloxyethyl phosphorylcholine)] (PMAMPC) prepared by “grafting to” method was an excellent sensor platform for detecting the target molecules in blood plasma. All results have demonstrated the potential of the carboxyl-containing brushes as SPR-precursor layer for biosensing applications.