Insulin adsorption on functionalized silica surfaces: an accelerated molecular dynamics study.

We study the influence of surface functionalization of a silica surface on insulin adsorption using accelerated molecular dynamics simulation. Three different functional groups are studied, CH3, OH, and COOH. Due to the partial charges of these groups, the surface polarity of silica is strongly altered. We find that the adsorption energies of insulin change in agreement with the decreasing surface polarity. Conformational changes in the adsorbed protein and the magnitude of the molecular dipole moment in the adsorbed state are consistent with this result. We conclude that protein adsorption on functionalized polar surfaces is governed by the induced changes in surface polarity.