title: Gradation of proteins and cells attached to the surface of bio-inert zwitterionic polymer brush.
abstract: A self-assembled monolayer (SAM) of a 2-bromoisobutyryl end group-carrying initiator for atom transfer radical polymerization (ATRP) was constructed on the surface of silicon wafer or glass substrates via a silane-coupling reaction. When the initiator SAM was irradiated with UV light at 254nm, the surface density of bromine atoms was reduced by the scission of CBr bonds as observed by XPS. With the surface-initiated ATRP of the zwitterionic vinyl monomer, carboxymethyl betaine (CMB), the surface density of PCMB brushes could be easily varied by changing the irradiation period of UV light prior to the polymerization. Furthermore, by using a UV-cut shutter sliding above the initiator SAM-modified substrate at a constant speed, the degree of bromine atom removal could be linearly varied along the direction of movement of the shutter. Consequently, the amount of both proteins adsorbed and cells adhered to the PCMB brush-covered substrate could easily be controlled by the gradation of the surface density of PCMB brushes, which suppressed protein adsorption and cell adhesion. Such a technique is very simple and useful for the regulation of the surface density of adsorbed proteins and adhered cells on an originally bio-inert surface.
authors.affiliation: Department of Advanced Nano- and Biosciences, Graduate School of Innovative Life Sciences, University of Toyama, Toyama 930-8555, Japan.
authors.forename: Lifu
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Advanced Nano- and Biosciences, Graduate School of Innovative Life Sciences, University of Toyama, Toyama 930-8555, Japan; Department of Applied Chemistry, Graduate School of Science and Engineering, University of Toyama, Toyama 930-8555, Japan; 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; Institute for Polymer-Water Interfaces, Fukujima 84, Yatsuo, Toyama 939-2376, Japan. Electronic address: kitano443116@gmail.com.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Kitano
authors.affiliation: Institute for Chemical Research, Kyoto University, Uji 611-0011, Japan.
authors.forename: Kohji
authors.initials: K
authors.lastname: Ohno
authors.affiliation: Electronics Materials Laboratory, Nissan Chemical Industries, Toyama 939-2792, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Kishioka
authors.affiliation: Electronics Materials Laboratory, Nissan Chemical Industries, Toyama 939-2792, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Usui
mesh_terms: D000327:Adsorption; D000818:Animals; D001622:Betaine / Q000737:chemistry / Q000494:pharmacology; D001672:Biocompatible Materials / Q000494:pharmacology*; D002417:Cattle; D002448:Cell Adhesion / Q000187:drug effects; D005453:Fluorescence; D051379:Mice; D041681:NIH 3T3 Cells; D056951:Photoelectron Spectroscopy; D058105:Polymerization / Q000528:radiation effects; D011108:Polymers / Q000737:chemistry / Q000494:pharmacology*; D012710:Serum Albumin, Bovine / Q000378:metabolism*; D013499:Surface Properties; D014466:Ultraviolet Rays
chemical_list: D001672:Biocompatible Materials; D011108:Polymers; D012710:Serum Albumin, Bovine; D001622:Betaine
keywords: Atom transfer radical polymerization; Cell adhesion; Gradation; Protein adsorption; UV irradiation; Zwitterionic polymer brush