No abstract

Titanium alloys, such as Ti-10Ta-2Nb-2Zr (TTNZ), are promising biomaterials due to their excellent biocompatibility and low Young’s modulus. The TTNZ samples herein were manufactured by selective laser melting and the novel material was evaluated as a dental implant in vitro and in vivo. The microstructure, mechanical properties, electrochemical behaviour, cytotoxicity, haemocompatibility and osteogenic differentiation were systematically investigated. Based on the tensile test results, the as-printed TTNZ samples had an elongation of 20.23% ± 1.95%, an ultimate tensile strength of 646.61 ± 24.96 MPa and a Young’s modulus of 23.72 ± 1.18 GPa. According to the biocompatible value, the as-printed TTNZ sample exhibited no cell cytotoxicity and it showed even better cell adhesion ability than that of the as-printed Ti-6Al-4 V and wrought Ti-6Al-4 V samples. The haemolysis percentage of the as-printed TTNZ sample was 0.629% ± 0.363%. Moreover, the as-printed TTNZ sample facilitated protein adsorption and osteogenic differentiation of human osteoblast-like (MG-63) cells in vitro. The in vivo data also demonstrated the histocompatibility of the as-printed TTNZ. In summary, the as-printed TTNZ developed in this study demonstrated good biocompatibility, low stress shielding, excellent ductility and great osteogenic differentiation. These results indicated that as-printed TTNZ alloys can be promising for end-use human biomedical applications.

The two major problems of titanium alloy surface of bone/dental implants were the lack of native tissue integration and associated infection. To solve these problems, the development of self-defending implants with intrinsic osteogenic properties has been highlighted, in which titanium alloy surfaces of bone/dental implants are endowed with antibacterial property by silver (Ag) incorporated in biomaterials. In this study, we biofunctionalized the surface of selective laser melting (SLM) manufactured volume-porous Ti-Ta-Nb-Zr scaffolds by using plasma electrolytic oxidation (PEO) as a way to eliminate the peri-operative bacterial load and promote osseointegration. In the experiment, the PEO process operated with three different concentration (1, 1, and 2 g/L) of a AgNO3 solution. As a result, a titanium oxide coating embedded with calcium and phosphorous and Ag was formed by one-step PEO treatment, and a presence of HAp was detected by X-ray diffraction (XRD) and XPS. In addition, Ag ions were found to be released from the scaffolds for at least 28 days, resulting in an effective prevention of bacterial adhesion and a decrease of the number of planktonic bacteria, with no sign of cytotoxicity shown simultaneously. Highly porosity micropores were formed on the surface of scaffolds after oxidation, and the mechanical properties did not show any signs of change. Besides, a strong calcium deposition and osteoconductive effect were found on the surface of PEO-treated Ag scaffolds. To sum up, this study reveals the potential of PEO coatings to biofunctionalize SLM Ti-Ta-Nb-Zr scaffolds with antibacterial agents. The biomaterials developed here, therefore, exploit the biofunctionalized behavior of Ag to offer strong antibacterial behavior and osteogenic promotion without cytotoxicity of Ag against mammalian cells.