UV-Patterning of Anti-Biofouling Zwitterionic Copolymer Layer with an Aromatic Anchor Group

A thin layer (around 2 nm in thickness) composed of a random copolymer of zwitterionic carboxymethyl betaine (CMB) and p-trimethoxysilylstyrene (STMS) (9:1) is constructed on a glass substrate or a silicon wafer. The copolymer layer is highly resistant against nonspecific adsorption of bovine serum albumin (BSA). However, on UV irradiation at 193 nm, the layer becomes hydrophobic and BSA is significantly adsorbed on the substrate. Upon UV irradiation through a photomask, a patterning of the fluorophore-labeled protein with a resolution of about 1 mu m can be clearly observed. On the other hand, the copolymer layer of CMB and 3-methacryloxypropyltrimethoxysilane (MPTMS) (9:1) without an aromatic group exhibit less distinct pattern. Further, the poly(CMB-gamma-STMS) layer decomposes more quickly compared with the poly(CMB-gamma-MPTMS) layer at low irradiation dose. The zwitterionic polymer layer with an aromatic anchor group will be used at the modification of substrates applicable to sensing devices.