Study of Bone Regeneration and Osteointegration Effect of a Novel Selective Laser-Melted Titanium-Tantalum-Niobium-Zirconium Alloy Scaffold

Titanium-tantalum-niobium-zirconium (Ti-Ta-Nb-Zr) alloy is a novel material currently available for orthopedic applications. However, these scaffolds, manufactured using traditional methods, present disadvantages such as irregular pore size, unsuitable mechanical features, and poor connectivity between pores. In this study, porous Ti-Ta-Nb-Zr (60% Ti, 2% Ta, 36% Nb, and 2% Zr) scaffolds were printed by selective laser melting (SLM) with a controllable pore size of 300-400 mu m. The mechanical properties of the SLM-manufactured scaffolds were evaluated, as well as its osteogenesis in vitro and osteointegration in vivo. Porous Ti-Ta-Nb-Zr scaffolds yielded superior cell proliferation and cell adhesion results with human bone mesenchymal stem cells (hBMSCs) compared with porous Ti6Al4V scaffolds. The osteogenic differentiation experiment demonstrated enhanced osteogenic differentiation of hBMSCs in the Ti-Ta-Nb-Zr group than in the Ti6Al4V group. After the porous Ti-Ta-Nb-Zr or control scaffolds were implanted into a cylindrical bone defect in the rabbit lateral femoral condyle, the initial radiological results confirmed the excellent osteogenic activity of the novel 3D-printed scaffolds. Histological analysis further indicated that the Ti-Ta-Nb-Zr scaffolds promoted bone regeneration and osteointegration more effectively than Ti6Al4V scaffolds. Our findings demonstrate that the SLM-manufactured porous Ti-Ta-Nb-Zr scaffold has considerable potential for clinical orthopedic application.