Amino acid adsorption on anatase (101) surface at vacuum and aqueous solution: a density functional study.

The adsorption of 20 amino acids (AAs) on the (101) surface of anatase titanium dioxide (TiO2) has been investigated under the scheme of density functional theory. Through the analysis of adsorption geometries, amino group and side chains of AAs have been identified as the major side to adsorb on TiO2, while the carboxyl group prefers to stay outside to avoid the repulsion between negatively charged oxygen from TiO2 and AAs. On the surface, two-coordinated oxygen is the major site to stabilize AAs through O-H interactions. The above conclusion does not change when it is in the aqueous solution based on the calculations with AAs surrounded by explicit water molecules. The above knowledge is helpful in predicting how AAs and even peptides adsorb on inorganic materials. Graphical abstract The adsorption of 20 amino acids (AAs) on the (101) surface of anatase titanium dioxide (TiO2) has been investigated under the scheme of density functional theory.