Magnetron sputtering to enhance bone integration of tantalum-coated titanium implants: an in vitro and in vivo analysis

Ti6Al4V (TC4) widely used in bone implants, has good mechanical properties but unremarkable bone-forming capacity. Tantalum (Ta) features excellent biocompatibility and suitability for osteogenesis, albeit with a significantly higher elastic-modulus. In this study, we combined the strengths of both materials to optimize implant materials. Magnetron sputtering was applied to deposit a Ta coating onto the TC4 surface (Ta-C-TC4). Surface characteristics were assessed via scanning electron microscope (SEM). Cell adhesion was assessed using SEM and cytoskeletal staining, while live/dead staining was used to evaluate cell viability and biocompatibility on the material surfaces. For proliferation analysis, fluorescence transfection and CCK-8 assay were utilized, while quantification of substance and qRT-PCR were employed to assess the osteogenic differentiation. In vivo, fluorescence labelling, VG, and Goldner staining were employed to evaluate bone integration. A 550 nm-thick Ta coating was successfully achieved on Ta-C-TC4, and its elements and morphology closely resembled Ta. Cells exhibited more pronounced proliferation and differentiation on Ta and Ta-C-TC4. More extensive encasement of new bone was observed around Ta and Ta-C-TC4. Ta-C-TC4 exhibits biocompatibility on par with Ta and demonstrates superior bone integration compared to TC4. Magnetron sputtering represents a promising strategy to harness the mechanical attributes of TC4 with the biological characteristics of Ta, thereby holding potential for the advancement of bone implant.