Effects due to interadsorbate interactions on the dipeptide/TiO2 surface binding mechanism investigated by molecular dynamics simulations

Classical molecular dynamics simulations, supported by ab initio periodic calculations, were carried out to investigate peptide adsorption mechanisms onto a rutile (110) TiO2 layer in the presence of water molecules. Different binding modes, comprising multiple coordination to the titanium atoms, of several conformers, simultaneously adsorbed upon the surface, were analyzed in detail. In agreement with experimental and theoretical findings, peptide carbonyl oxygens and nitrogens were found to be possible coordination atoms. Local effects were responsible of adsorption and desorption events and intermolecular interactions induced conformational changes and reorientations of the molecules with respect to the surface that produced both strongly and weakly adsorbed species.