title: Patterning of photocleavable zwitterionic polymer brush fabricated on silicon wafer.
abstract: Brushes of a polymer, namely poly(carboxymethylbetaine) (PCMB), were fabricated on silicon wafers by reversible addition-fragmentation chain-transfer (RAFT) polymerization using a surface-confined RAFT agent having an aromatic group at its bottom. The polymer brush showed effective suppression of the non-specific adsorption of bovine serum albumin (BSA) and adhesion of fibroblasts (3T3 cells). In contrast, BSA and 3T3 cells significantly adsorbed on and adhered to positively or negatively charged polymer brushes fabricated by the same procedure. Upon UV irradiation at 193 nm, the thickness of the PCMB brush with an aromatic group at its bottom decreased significantly whereas PCMB prepared using a surface-confined RAFT agent without an aromatic group needed a much higher irradiation dose to afford a comparable decrease in thickness. These results indicate a preferential cleavage of the PCMB brush due to photodecomposition of the phenyl group at the bottom. BSA and 3T3 cells non-specifically adsorbed on and adhered to the UV irradiation-induced hollow spaces, respectively. Furthermore, a designed pattern with a resolution of 5 μm was successfully made on the PCMB brush above the silicon wafer by simple UV irradiation. These results suggest that the surface-confined aromatic RAFT agent will be quite useful for simple photolithography in biomedical fields.
authors.affiliation: Department of Applied Chemistry, Graduate School of Science and Engineering, University of Toyama, Toyama 930-8555, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Kamada
authors.affiliation: Department of Applied Chemistry, Graduate School of Science and Engineering, University of Toyama, Toyama 930-8555, Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Yamazawa
authors.affiliation: Frontier Research Core for Life Sciences, University of Toyama, Toyama 930-8555, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Nakaji-Hirabayashi
authors.affiliation: Department of Applied Chemistry, Graduate School of Science and Engineering, University of Toyama, Toyama 930-8555, Japan. Electronic address: kitano@eng.u-toyama.ac.jp.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Kitano
authors.affiliation: Electronics Materials Laboratory, Nissan Chemical Industry, Toyama 939-2792, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Usui
authors.affiliation: Electronics Materials Laboratory, Nissan Chemical Industry, Toyama 939-2792, Japan.
authors.forename: Yoshiomi
authors.initials: Y
authors.lastname: Hiroi
authors.affiliation: Electronics Materials Laboratory, Nissan Chemical Industry, Toyama 939-2792, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Kishioka
mesh_terms: D058105:Polymerization; D011108:Polymers / Q000737:chemistry*; D012825:Silicon / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D011108:Polymers; D012825:Silicon
keywords: Patterning; Photocleavage; RAFT; Zwitterionic polymer brush.