Resistance to nonspecific protein adsorption by poly(vinyl alcohol) thin films adsorbed to a poly(styrene) support matrix studied using surface plasmon resonance

Thin films of poly(vinyl alcohol) (PVA) polymer were prepared on a flat, no nporous, poly(styrene) support matrix by adsorption from aqueous solution a nd were characterized in order to investigate the nonspecific adsorption of proteins to a chromatographically relevant surface. The integrity and surf ace coverage of the PVA thin films were established by surface analysis and atomic force microscopy imaging. The adsorption of the PVA polymers to the poly(styrene) substrate and the nonspecific adsorption of proteins to the PVA-coated surface were monitored using surface plasmon resonance. PVA was strongly bound to the poly(styrene) surface, but the surface density of the adsorbed PVA polymers was affected substantially by the concentration, mol ecular weight, and degree of hydrolysis of PVA polymers used. There was evi dence of increasing degrees of unfolding of the PVA polymer onto the poly(s tyrene) surface as the concentration of the the PVA coating solution increa sed. Complete PVA coverage of the poly(styrene) surface was observed at PVA concentrations of 0.1 mg/mL or greater but with significant influence of b oth molecular weight and degree of hydrolysis of the PVA polymers. Resistan ce of the PVA-coated poly(styrene) surface to the nonspecific adsorption of human serum albumin (HSA) correlated with the degree of surface coverage o f the PVA. The use of anti-HSA as a probe for adsorbed HSA suggested that H SA was displacing PVA from the poly(styrene) surface at the lower PVA surfa ce coverage. A complete barrier to nonspecific protein adsorption was obser ved with a PVA coating solution concentration of greater than 0.1 mg/ mL wi th a degree of hydrolysis of < 88%.