DFT computational study of the RGD peptide interaction with the rutile TiO2 (110) surface

Planewave DFT calculations including ab initio molecular dynamics (AIMD) were used to model the adsorption of a biologically relevant peptide sequence, arginine-glycine-aspartic acid (RGD), upon a rutile TiO2 (110) surface. It was found that binding is solely through the aspartic acid end of the RGD. The carboxy groups bind through dissociative bridging and molecular forms, similar to formic acid. The energy of adsorption is much smaller (0.5–0.77 eV) than seen for formic acid and the molecular adsorption is the strongest adsorption mode. Neutral adsorption is favoured over zwitterionic adsorption and adsorption through the carboxy group of the aspartic acid side chain rather than the terminal carboxy group is favoured due to a configuration allowing an additional surface–carbonyl bond. The RGD backbone is not significantly disrupted upon adsorption.