A kinetic model of protein adsorption/surface-induced transition kinetics evaluated by the scaled particle theory

The adsorption of proteins and other large molecules at the liquid-solid in terface often involves a surface-induced transition in either internal conf ormation or molecular orientation. Recently, Van Tassel et al. modeled this adsorption/transition process as the sequential surface placement of sprea ding disks. In this work, we employ the scaled particle theory (SPT) to der ive approximate analytical expressions for the probability functions appear ing in the kinetic equations for this model system. Specifically, the proba bility functions governing the adsorption and spreading events are calculat ed in terms of the reversible work required to create cavities in a binary system of spread and unspread disks. Compared to those derived earlier via a density expansion theory (DET), the SPT approximated probability function s are simpler and more accurate (compared to simulation), and are applicabl e over a wider set of parameter values. (C) 1999 Academic Press.