Device-related infection or inflammatory and stress shield are still the main problems faced by titanium alloy implants for long-term implantation application; therefore, it is of great significance to design an alloy with low elastic modulus and good antibacterial properties as well as good biocompatibility. In this paper, Ti-13Nb-13Zr-xCu(x = 3, 7 wt.%) alloys were designed and prepared to reveal the influence of Cu content on the elastic modulus and antibacterial property. X-ray diffractometer, metallographic microscope, scanning electron microscope, and transmission electron microscope were used to study the phase transformation, microstructure, mechanical properties, antibacterial properties, and cytotoxicity of the alloys. The experimental results have demonstrated that the antibacterial performance and the elastic modulus were significantly improved but the corrosion resistance deteriorated with the increase of the copper content. Ti-13Nb-13Zr-3Cu with a low modulus of 73 GPa and an antibacterial rate of over 90% against Staphylococcus aureus (S. aureus) exhibited great potential as a candidate for implant titanium in the future.

Although Ti-Cu alloys have been shown to possess good antibacterial properties, they are still biologically inert. In this study, sandblasting and acid etching combined with anodic oxidation were applied to roughen the surface as well as to form a TiO₂/CuO/Cu₂O composite film, which would benefit both the antibacterial properties and the biocompatibility. The surface morphology, the phase composition, and the physicochemical properties were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Electrochemical testing and inductively coupled plasma spectrometry (ICP) were used to determine the corrosion resistance and Cu ion release, the plate counting method was used to evaluate the antibacterial performance, and the CCK-8 method was used to evaluate the cytocompatibility. It was revealed that a rough surface with densely porous double layer composed of TiO₂/CuO/Cu₂O was produced on Ti-Cu alloy surface after the combined surface modification, which enhanced the corrosion resistance significantly. The plate counting results demonstrated that the modified sample had strong long-term antibacterial performance (antibacterial rate > 99%), which was attributed to the formation of TiO₂/CuO/Cu₂O composite film. The cell compatibility evaluation results indicated that the surface modification improved the cytocompatibility. It was demonstrated that the combined modification provided very strong antibacterial ability and good cytocompatiblity, potentially making it a good candidate surface modification technique for Ti-Cu alloy for biomedical applications.