The role of electrolytes on protein adsorption at a hydrophilic solid–water interface

The adsorption of four proteins, RNase A, HEWL, BSA, and β-Lac, was examined on the surface of a negatively charged SiO2/TiO2 optical waveguide. The amount of adsorbed protein followed the salt series Mg2+ > Li+ > Na+ > K+ and for anions Cl− > Br− > I−. This ordering was attributed to protein adsorption being primarily influenced by changes in hydrophobic interactions between the surface and the protein resulting from differences in water structure arising from the presence of electrolytes.