Factors affecting nonspecific interaction of BSA with solid surfaces: An SPR study

The kinetics of albumin absorption onto various solid surfaces was studied with the surface plasmon resonance technique (SPR). The following types of the samples were used in the absorption experiments: as-deposited gold layers, gold layers after oxidative washing, hydrophobic and hydrophilic plasma polymers. Absorption of the protein onto each of these surfaces was found to have some distinguishing features. The fastest kinetics and themaximum protein coverage were observed in the case of the gold layers without any pretreatment. By contrast, the absorption was almost completely suppressed in the case of the hydrophilic polymer overlayer. In addition, the effects and poly(ethylene glycol) or toluene added to thesolutions were investigated. The presence of the toluene caused negligible changes in the absorption kinetics while the absorption was substantially suppressed in presence of poly(ethylene glycol). Possible mechanisms ofnonspecific protein-surface interactions are analyzed in order to explain the observed differences in sorption behavior.