Proteins at interfaces : modelling of the residence time effect and experimental studies

Abstract: The residence time effect plays an important role in desorption phenomena at solid­ liquid interfaces. The objective of this work is to set up simple models to describe the dynamics of both adsorption and desorption of proteins on a solid surface. The main feature of such a mode] is to account for the capability of a molecule to change conformation through a single step process. The kinetics of desorption and the residence time effects are then studied by comparison of experimental data to the ideal scenario provided by the model. Data collected by means of off-null ellipsometry were used to illustrate the different desorption behaviours depending on the properties of the surface.Furthermore we introduce a method to use the Quartz Crystal Microbalance (QCM) for online monitoring of adsorption phenomena. We also show that porous gold electrodes improve the sensitivity of the QCM upon measuring the binding of antigens to antibodies. Real time measurement lie at the basis of the understanding and description of kinetic processes.