Adsorption of bovine serum albumin on previously formed PAH/PSS multilayer: A stagnation point optical reflectometry study

The method of stagnation point optical reflectometry was applied for investigation of adsorption of bovine serum albumin (BSA) on previously formed poly(allylamine hydrochloride)/poly(sodium 4-styrenesulphonate) (PAH/PSS) multilayer with PAH being a terminal layer. The solid substrate was silica in the form of silicon wafers carrying an oxide layer. In order to interpret the adsorption of BSA, the build-up mechanism of PAH/PSS multilayers was examined with special emphasis on the effect of electrolyte concentration, pH of solution, and the anchoring (precursor) layer on that process. Additionally, the effect of BSA concentration and of the anchoring layer on BSA adsorption was investigated. It was shown that in all investigated systems the adsorption of BSA depends on conditions under which the multilayer was formed (ionic strength, pH and presence of an anchoring layer), as well as on BSA concentration. It follows that adsorption of BSA could be controlled not only by choosing suitable BSA concentration, but also by modifying the preformed multilayer.