Kinetic model for the simulation of hen egg white lysozyme adsorption at solid/water interface

Abstract

A simulation model for adsorption kinetics of hen egg white lysozyme (HEW) adsorption to hydrophilic silica is proposed. The adsorption kinetic data were monitored by using in-situ ellipsometry. The model is based on an irreversible adsorption mechanism allowing two different adsorbed states. The adsorbed states were differentiated based on binding strengths resistant to the concentration gradient exerted by rinse. Molecules desorbing and remaining upon rinse were identified as loosely bound (state 1) and tightly bound (state 2) states, respectively. The adsorption rate constants were assumed to be a time-dependent nonlinear function in order to account for the change in surface properties originating from the protein layer formed on the surface. The parameters of adsorption rate constants were evaluated by using adsorption kinetic data at different protein concentrations, and the relationships between the adsorption parameters and protein concentration were established which eventually demonstrated a linear relation- ship. The established relations between the adsorption parameters and concentration elucidated the effect of protein concentration on adsorption to hydrophilic silica.