Novel immobilizations of an adhesion peptide on the TiO2 surface: An XPS investigation

The covalent attachment of an adhesive peptide, reproducing the 351-359 sequence of human vitronectin, to oxidized titanium surfaces was investigated by XPS spectroscopy. The peptide enhances osteoblast adhesion to titanium, the most used biomaterial for implants and prostheses. Core level spectra of the TiO2 surface and of the biomimetic surface were investigated. Novel selective covalent immobilization of (351-359) HVP was carried out by treatment of the TiO2 surface with (3-aminopropyl) triethoxysilane, glutaric anhydride and a side chain protected peptide sequence presenting only a free terminal amino group, followed by side chain deprotection. An alternative strategy for covalent attachment consists in photoactivation of physisorbed (351-359) HVP directly on the TiO2 surface; samples were incubated with HVP solution and subsequently irradiated with UV light. A comparison with the results previously obtained for nonselective HVP immobilization will be discussed