Competitive adsorption of proteins on hydrogel contact lenses.

Abstract

PURPOSE: To compare sequential and competitive adsorption of some proteins onto hydrogel contact lenses. METHODS: New, never-worn, group IV soft contact lenses were incubated in freshly prepared solutions of lysozyme, alpha-lactalbumin, and ribonuclease at room temperature for 5 days with constant shaking, during which time their adsorbed protein was directly measured using UV absorbances at 280 nm. Adsorption isotherms were prepared. The lenses were rinsed with distilled water following a second protein treatment. RESULTS: We found that the chemical composition of the lens and the charge of the previously adsorbed protein affected sequential and competitive adsorption of proteins on a contact lens surface. CONCLUSIONS: Sequential adsorption occurs only if the second protein has a more favorable electrostatic interaction; sequential adsorption involves almost total displacement of the preadsorbed protein.