Formation of non-biofouling, polymeric films, and their applications to selective immobilization of biomacromolecules

Abstract

We report the formation of nonbiofouling, polymeric films, and their applications to selective immobilization of biomacromolecules such as protein and cell. Chapter 2 describes the formation of the biocompatible, nonbiofouling pOEMGA films by SIP of oligo(ethylene glycol) methyl ether methacrylate (OEGMEMA) and subsequently click chemistry for bioconjugation. Chapter 3 describes the covalent bonding of a random copolymer, poly(PEGMA-r-NAS), by “grafting onto” approach on amine-terminated monolayers and the application to selective immobilization of biological materials. In chapter 2 we report the introduction of biotin as bio-ligand on the nonbiofouling pOEGMA films formed by SIP of OEGMA and subsequently the application of click chemistry for selective immobilization of streptavidin on gold substrates. A thin film of a biocompatible and nonbiofouling poly(oligo(ethylene glycol) methyl ether methacrylate) (pOEGMA) was formed on a gold surface by a combination of the formation of self-assembled monolayers terminating in bromoester―an initiator of atom transfer radical polymerization (ATRP)―and surface-initiated, aqueous ATRP. After the formation of the pOEGMA film, the terminal bromide group of pOEGMA was transformed to the azide group by the reaction with $NaN_3$, and the Sharpless “click”chemistry, triazole formation between azide groups and acetylene groups, was investigated as an approach to bioconjugation. We tested five acetylene group-containing compounds bearing different functionalities, such as methyl, hydroxyl, carboxylic acid, ester, and biotin groups. The non-biofouling effect of the pOEGMA thin films against proteins (bovine serum albumin, fibrinogen, lysozyme, and ribonuclease A, and streptavidin) was confirmed at each step of the processes by ellipsometric measurements, and the specific binding of streptavidin to the biotin-presenting surface was investigated by surface plasmon resonance spectroscopy and enzyme-linked immunosorbent assay. The ...