Enhanced osteointegration of tantalum-modified titanium implants with micro/nano-topography

Abstract

Numerous approaches have been used to modify titanium implant surfaces to achieve better osteointegration. In this study, commonly used sandblasted, large grid acid etched (SLA) titanium implants were modified with bioactive trace elements in combination with surface micro/nano-topographical modifications to enhance the osteointegration and antibacterial activity. Briefly, tantalum (Ta) was implanted onto SLA titanium (SLA-Ta) by magnetron sputtering. The modified surface was characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The electrochemical corrosion properties of two surfaces were measured. The effects of the SLA-Ta surface on rat bone marrow mesenchymal stem cells (rBMSCs), including cell adhesion and proliferation, osteogenic-related gene expression, alkaline phosphatase activity, alizarin red staining, and the immunofluorescence of osteopontin and osteocalcin, were investigated. In addition, the influence of the Wnt/β-catenin pathway in this process was explored using western blotting. The SEM and XPS results revealed that Ta₂O₅ with micro/nanoscale-topography was established on the titanium surface. A potentiodynamic polarization study indicated the better corrosion resistance of the modified SLA-Ta surface. Importantly, the SLA-Ta structure not only significantly promoted the initial adhesion activity and proliferation of rBMSCs, but also enhanced osteogenic gene and protein expression, reflecting osteogenic function. Western blot results suggested the possible mechanism of the SLA-Ta surface induced osteogenic differentiation might be the activation of the Wnt/ILK-β-catenin pathway. These results suggest our developed SLA-Ta surface offers remarkable osteogenic activity and shows great potential for application in orthopaedic and dental implants.