Fabrication And Biological Characterization Of Ta Micro/nano Hierarchical Composite Coating

At present, titanium and its alloys were widely used as the bone repair materials due to the excellent mechanical strength and low surgical infection rate. Unfortunately, as the inert medical material, titanium and its alloys were found to be difficult to bond with the autologous tissues effectively after impla ntation, which may lead to the engraftment failure and some adverse reactions such as subcutaneous effusion.In the previous study, the surface morphology of materials, especially, materials with micro/nano hierarchical was found significative for the protein adsorption promotion and cell adhesion or differentiation, because such materials can simulate the cell growth environment of animals. Therefore, materials with micro/nano hierarchical were believed to be the development tendency in the development of implant in the future.Traditional treatment of titanium surface involved the preparation of biological ceramic coatings, in order to enhance the biocompatibility; however, the coatings may easily degradation in vivo and make it difficult for long term therapy because of the low bonding strength between the coatings and substrate. Moreover, as one of the “biophilic metals", titanium metal provides the solution for this problem, due to its good biocompatibility, outstanding physiological environment stability and organism friendly.In this research, we focused on the solution of existing drawbacks of bone repair materials titanium and its alloys, applied the plasma spray to afford the pure tantalum coatings and composite coatings with micro/nano hierarchical that have a higher protein activity and cellular activity in order to achieve the purpose of improving the biological activity of titanium-based implants. And we solved the postoperative complications of the titanium base repair materials successfully, together with very high osteogenic activity.Detailedly, we applied the anodic oxidation and alkali heat treatment to afford the micro/nano hierarchical of tantalum surface and then verified the good protein activity of tantalum surface with micro/nano hierarchical. In addition, we prepared the tantalum coatings on titanium substrates by plasma spraying, and determined the parameters in order to prepare the Ta/HA composite coatings with different components. We characterized the physicochemical properties of p ure tantalum coatings and composite coatings by SEM and XRD, and evaluated the biological performance of prepared coatings.The results showed that, the plasma spraying can prepare the good bioactivity pure tantalum coatings or composite coatings on titanium after the optimization of parameters. Prepared composite coatings were found with excellent biocompatibility and mineralization performance that far superior to pure titanium materials. Meanwhile, the bond strength of composite coatings are 1.5 times than pure HA coatings, affording the solution to the unsatisfactory osteogenic capability of pure tantalum coatings and the low coating strength of bio-ceramic coatings.This study provides the experimental and theoretical basis for the clinical application of titanium- modified materials.