Promotion of osteogenic differentiation and bone healing in tantalum-coated 3D-printed Ti6Al4V alloy scaffolds using chemical vapor deposition

• Preparation technology of tantalum coating on titanium alloys was first overcome. • Tantalum coating with high purity and bond strength was prepared on titanium alloys. • Dissolution of toxic element vanadium was effectively blocked by tantalum coating. • Tantalum coating could promote the rapid integration of prosthesis and bone. • Tantalum coating could significantly promote metal-bone interface integration. Large bone defects necessitate medical intervention due to limited self-healing. Tantalum (Ta) offers biocompatibility and bioactivity but is hindered by high modulus, density, and cost. We applied Ta coatings of varying thicknesses to 3D-printed porous Ti6Al4V scaffolds using chemical vapor deposition to enhance the biological activity of titanium alloy scaffolds. Uniform and dense Ta coatings with high purity and interfacial adhesion were successfully prepared on the surfaces of porous titanium alloys. When the thickness of the Ta layer was 15 μm, the average compressive strength reached the maximum value of approximately 120 MPa. Additionally, the dissolution of harmful Vanadium ions from the matrix was effectively suppressed. In vitro cell experiments showed that the Ta coating on the titanium alloy surface was beneficial to cell adhesion and proliferation and significantly promoted the osteogenic differentiation of rabbit bone marrow mesenchymal stem cells. Moreover, the osteogenic differentiation ability was enhanced as the thickness of the coating increased. Animal experiments further confirmed that 15-μm-thick Ta-coated scaffolds significantly promoted new bone formation and metal-bone interface integration compared to uncoated scaffolds. This study identifies 15 μm as the optimal Ta coating thickness for maximizing osteogenic function, providing a novel theoretical foundation for clinical prosthesis design.