A generic method was described to change surface biocompatibility by introducing reactive functional groups onto surfaces of polymeric substrates and covalently binding them with biomolecules. A block copolymer with protected carboxylic acid functionality

poly(styrene-b-tert-butyl acrylate) (PS-PtBA)

was spin coated from solutions in toluene on a bioinert polystyrene (PS) substrate to form a bilayer structure: a surface layer of the poly(tert-butyl acrylate) (PtBA) blocks that order at the air-polymer interface and a bottom layer of the PS blocks that entangle with the PS substrate. The thickness of the PtBA layer and the area density of tert-butyl ester groups of PtBA increased linearly with the concentration of the spin coating solution until a 2 nm saturated monolayer coverage of PtBA was achieved at the concentration of 0.4% W/W. The protected carboxylic acid groups were generated by exposing the tert-butyl ester groups of PtBA to trifluoroacetic acid (TFA) for bioconjugation with FMRF peptides via amide bonds. The yield of the bioconjugation reaction for the saturated surface was calculated to be 37.1% based on X-ray photoelectron spectroscopy (XPS) measurements. The success of each functionalization step was demonstrated and characterized by XPS and contact angle measurements. This polymer functionalization/modification concept can be virtually applied to any polymeric substrate by choosing appropriate functional block copolymers and biomolecules to attain novel biocompatibility.