Nanoporous alkoxy-derived titanium oxide coating: a reactive overlayer for functionalizing titanium surface

Effective immobilization of bioactive substances such as adhesive proteins, synthetic peptides and growth factors on metallic substrates is required for a number of medical applications. In the present work, evidence is presented to show that an alkoxy-derived nano-porous titanium oxide coating, synthesized electrochemically on titanium in methanolic electrolytes, may act as an effective interface for functionalizing a titanium surface. It is demonstrated that nanoporous oxide coatings could facilitate fast diffusion of small organic molecules within the oxide network and form strong chemical bonds with the functional groups of these molecules at room temperature. Fourier transformed-infrared spectroscopy was used to investigate the nature of the interfacial interactions between the oxide network and a range of molecules containing COOH, OH, NH2, C=O and phosphoric acid functional groups. The results indicate that the nanometre-sized oxide clusters within the coating may play an essential role in effective immobilization of organic molecules by providing numerous binding sites for chemisorption of these species. The surface-derivatized oxide coating may provide a solid phase for the subsequent attachment of a broad range of biochemically active molecules on the titanium surface.