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

Abstract

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 Ti_0.95Nb_0.95O₄ 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.