Kinetic model for serum albumin adsorption : experimental verification

Abstract

When human serum albumin is adsorbed at a hydrated metal oxide surface, the amounts which can be desorbed by replacing the protein solution with pure solvent steadily decrease. A quantitative kinetic model involving two modes of adsorption, reversible and irreversible, is inferred, and tested by allowing the adsorption and desorption to take place on the surface of planar optical waveguides, and determining the surface coverage from the shift in the mode indices of guided waves due to the adsorption. The method allows the surface coverage to be determined to a precision of ca. 1 ng cm^–2 every 15–30 s. Excellent agreement with the model was obtained.