Dual-functional boronized Ti6Al4V/FHA composites: Synergistic enhancement of osteogenesis and antibacterial activity

To address the issue of implant failure caused by insufficient bioactivity or infection-induced poor osseointegration during the implantation of titanium implants which are widely used, this study proposed a fluorine-substitution based boronization modification strategy for titanium implants. It involved substituing the hydroxyl group in hydroxyapatite (HA) through solution synthesis, where fluorine with varying substitution percentages, including 0, 25%, 50%, 75%, and 100%, were systematically incorporated to synthesize nano-fluoridated hydroxyapatite (FHA). Combined with titanium alloy and TiB 2 as the main raw materials, novel Ti6Al4V/FHA composites as implants were prepared using the microwave sintering technique. When the substitution percentage of fluorine was 50%, the lattice defects of the composite could be reduced, with minimized impurity incorporation, resulting in a higher crystallinity and a more stable apatite structure. Meanwhile, more TiB 2 was converted into TiB, endowing the Ti6Al4V/FHA composite with improved mechanical properties and biocompatibility. This approach promoted the adhesion, proliferation, differentiation, and mineralization of osteoblasts on the composite surface, as well as the removal of bacteria. These findings provided valuable insights for the development of novel titanium-based composites with both great osteogenic and antibacterial properties.