Attachment of biotin on silicon surface-tethered poly(acrylic acid) brushes

Abstract

Surface-tethered poly(acrylic acid) (PAA) brushed can potentially be used as functional nanometer-thick film for many technological applications. Their carboxyl groups serve as versatile moieties for a wide range of chemical modificantion including an attachment of biomolecules. In this research, linear and branched poly(tert-butyl acrylate) (PtBuA) brushed were prepared by surface-intiated atom transfer radical polymerization of tert-butyl acrylate and self-condensing vinyl copolymerization of PtBuA with acrylic acid 2-(2-bromopropionyloxy)ethyl ester (BPEA), respectively. Linear and branced PAA brushed were subsequently obtained after tert-butyl groups of PtBuA brushes were removed by acid hydrolysis. The carboxyl group density of linear and branched PAA brushes can be varied as a function of chain length (MW) and comonomer ration (grammar), respectively. The success of biotin attachment to the carboxyl groups of both linear and branched PAA brusheswas verified by FT-IR analysis and the binding with fluorescein-conjugated streptevidin which was visualized by fluorescence microscope.