Title : An insight on the stability of titanium-oxide based implant material
Abstract:
The invention and integration of medical implants have made a huge revolt in modern medicine by offering new opportunities in curing chronic illnesses and restoration of bodily functions. Commercially pure titanium and its alloys are the widely used implant materials owing to their high corrosion resistance and biocompatibility. It is the thin oxide film primarily made up of TiO2 which forms spontaneously on the surface of titanium act as a protective barrier against the aggressive environments and contribute to its corrosion resistance. So, it is crucial to comprehend how the alteration in surface chemistry (oxides in varying oxidation state and composition) could affect titanium’s defense mechanism on inflammatory conditions and resulting reactive species like hydrogen peroxide (H2O2). In the current work we have explored the long-term stability of sputter coated thin film titanium-oxide (TiO2, Ti2O3 and TiO) substrates by exposing to phosphate buffered saline solution (PBS) with or without the addition of 1mM H2O2 for 5 days. X-ray photoelectron spectroscopy (XPS) was performed to understand the variation in the surface chemistry. The results revealed the presence of TiO2, and Ti2O3 on the bare substrate (without H2O2), while additional peaks of TiO and Ti was found on substrate exposed to H2O2, suggesting the risk of reduction. The electrochemical characterizations such as cyclic voltammetry, Tafel plot and impedance spectroscopy also indicated the interruption of corrosion resistance in the presence of H2O2. Density functional theory (DFT) was employed to delineate surface interactions between titanium oxide surface and H2O2. We believe that this work provides a deeper understanding of the biological mechanisms involved in titanium-oxide based implants allowing to forecast their biosafety and aid in the design of better implants.
