Transformative Bioactive Wear Resistant Ti₃Au:N and Ti₃Au:O Coatings for Medical Implants and Devices.

Abstract

Current biomedical implants have high mechanical strength and corrosion resistance, but are highly susceptible to wear and lack antimicrobial properties to fight infection. Here, nitrogen and oxygen-doped Ti₃Au structures are successfully grown with increased dislocation slip plane energy and α-phase stability for the first time to achieve exceptional biotribological and antibacterial performance. The new Ti₃Au:N and Ti₃Au:O coatings are grown on Ti-6Al-4 V substrates via magnetron co-sputtering of Ti/Au in Ar:N₂ and Ar:O₂ environments at 450 °C and characterized for structural, chemical, tribomechanical, biocompatibility, and antibacterial properties. The reactive gas environments produce highly crystalline Ti₃Au:N and Ti₃Au:O coatings containing α-Ti₃Au phases, with partial columnar structures. All coatings present extremely safe cytotoxicity profiles with leached ion concentrations <0.2 ppm, and antibacterial performance like pure Cu and Ag, with a drastic reduction in bacterial colonies within 20 min of exposure. Nitriding and oxidizing the Ti₃Au coating produces superhard scratch-resistant surfaces with wear rates >20 times lower than the Ti-6Al-4 V substrate. The findings demonstrate new biocompatible Ti₃Au:N and Ti₃Au:O coatings with outstanding multifunctional biotribological and antibacterial properties with the potential to significantly extend the lifetime of medical implants and devices, such as joint replacements, bone screws, and surgical devices.