MANIPULATION OF HYDROPHOBIC INTERACTIONS IN PROTEIN ADSORPTION

The generally positive correlation between the extent of protein adsorption and the hydrophobicity of the adsorbent surface suggests that the hydrophobic interaction is a major driving force for adsorption. The customary approach to evaluating the role of this force, comparison of protein adsorption to a spectrum of solid surfaces spanning a range of hydrophobicities, is limited by incomplete control over surface chemical variables other than the overall hydrophobicity. We evaluate the importance of the hydrophobic interaction in protein adsorption, while maintaining constant surface properties, by addition of alcohols known to modulate the strength of the hydrophobic interaction in aqueous solutions. The responses of adsorption isotherms, dynamics, and lateral mobility of adsorbed proteins to changes in solvent composition demonstrate the primary role of the hydrophobic interaction in the adsorption of ribonuclease A to polystyrene surfaces. Manipulating the magnitude of the hydrophobic interaction alters the adsorption mechanism through both fluid-phase transport and protein binding at the interface.