SURFACE HYDROGELATION OF THIOLATED WATER-SOLUBLE COPOLYMERS ON GOLD

This paper reports a surface process technology that simultaneously en ables the formation of a hydrogel and its fixation on the surface of g old substrates. The technology utilizes two different chemical reactio ns of thiols: oxidation-induced disulfide bond formation and chemisorp tion on gold. Thiol-derivatized poly (vinyl alcohol)s (SH-PVAs), which were synthesized by radical copolymerization of vinylbenzyl N,N-dieth yldithiocarbamate and vinyl acetate, followed by alkaline hydrolysis, were coated on gold surfaces and then air-dried at room temperature. X -ray photoelectron spectroscopy (XPS) analyses and water contact angle measurements of a gold surface before and after treatment with SH-PVA provided evidence that a hydrogel was formed and fixed on the gold su rface. Atomic force microscopic (AFM) observations showed that the gel was tightly fixed even after thorough washing with hot water. Surface s with regional hydrogelation, which were prepared on a gold-deposited micropatterned polymer, were visualized by cellular patterning under a phase-contrast microscope and by fluorescein-labeled protein immobil ization under a fluorescent microscope.