Triple-synergistic smart coating on hierarchical porous Ti[sbnd]15Ta implants: Toward integrated antibacterial, corrosion-resistant and wear-resistant performance

To address revision challenges in traditional bone implants (bacterial infection, corrosion failure, and wear-induced loosening), hierarchical macro-micro-nano porous Ti[sbnd]15Ta alloys were fabricated via polyvinyl alcohol (PVA)-assisted sintering and surface etching. A silver nanoparticle (Ag NPs)-loaded sodium alginate (SA)-0.75 % polyethylene glycol (PEG)/polyvinylpyrrolidone (PVP) composite coating, which was constructed for the first time, was applied on the surface to integrate antibacterial, corrosion-resistant, and wear-resistant functions. Results showed the 15 wt% PVA-modified hierarchical porous Ti[sbnd]15Ta alloy, with 48.8 % porosity, 120 MPa compressive strength, and 17.8 GPa elastic modulus, achieved mechanical matching with human cortical bone. Surface-modified SA-0.75 %PEG/PVP coatings exhibited broad-spectrum antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) via 37 °C-triggered Ag⁺ release. In simulated body fluid (SBF), they demonstrated superior corrosion and wear resistance: corrosion current density was 9.71 × 10⁻⁷ A·cm⁻², and polarization resistance was 8.6 × 10³ Ω·cm⁻² (both significantly superior than uncoated alloys), and wear rate was reduced to 5.0 × 10⁻⁵ ± 0.2 mm³/(N·m), meeting clinical implantation thresholds. This synergistic integration of mechanically adapted substrate and multifunctional coating establishes a new paradigm for long-term implant stability.