Refining nanotopographical features on bone implant surfaces by altering surface chemical compositions

Surface nanotopographic and chemical modification are the most often used strategies to improve the performance of the currently used implants due to the well-documented effects of nanotopographic features and surface chemistry on the osseointegration of dental and orthopaedic implants. In this study, a dual-modification of surface chemistry and nanotopography was realized in one single process and a correlation between the surface chemistry and nanotopography was found. We used Nb2O5 to change the surface chemical composition of the plasma sprayed TiO2 coatings, which in turn refined the shapes and sizes of nanotopographic features due to the modulation of the rapid solidification process of plasma spraying. The refinement of nanotopographic features is dose-dependent, and the most prominent effect is found at the 50 wt% Nb2O5 doping where a solid solution with a formula of Ti0.95Nb0.95O4 was formed. The introduction of Nb2O5 into the TiO2 matrix also enhanced the corrosion resistance of TiO2 coatings and improved the bonding strength between the coating and the substrate, which are also dose-dependent. Moreover, it was found that cells on the 50 wt% Nb2O5/TiO2 coating with a nanoplate structure showed the highest viability over the culture period. This study demonstrates the potential use of TiO2 coatings doped with Nb2O5 for enhancing the bioactivity of the currently used metallic dental and orthopaedic implants.