Ti-15Zr-5.5Cu: A dental titanium alloy with robust antibacterial activity and superior corrosion resistance

Ti-15Zr-5.5Cu alloys were fabricated via vacuum self-consumable arc melting, yielding a yield strength of 780 ± 10 MPa and tensile strength of 845 ± 8 MPa, indicating excellent tensile properties and plasticity. Antibacterial performance was evaluated against Porphyromonas gingivalis, showing 89% inhibition of adherent bacteria and 12% inhibition of planktonic bacteria after 24 h. Mechanistic studies revealed that Cu incorporation induced oxidative stress, evidenced by elevated reactive oxygen species (ROS) fluorescence, increased protein, and reducing sugar leakage, and enhanced lipid peroxidation, leading to bacterial membrane damage and permeability increase. Corrosion tests demonstrated that Ti-15Zr-5.5Cu alloys exhibited superior resistance compared to pure Ti and Ti-15Zr, particularly in H₂O₂-rich environments. Electrochemical tests in artificial saliva, with and without 200 μM H₂O₂, revealed superior corrosion resistance, with a charge transfer resistance (Rip) reaching 29.2 × 10⁵ Ω·cm² (in standard saliva) and 52.59 × 10⁵ Ω·cm² (in H₂O₂-containing saliva) after 5 days, significantly higher than control materials. These findings elucidate the antibacterial mechanisms of Cu-containing biomedical alloys and provide guidance for the design of next-generation dental and orthopedic implants.