The effects of TiO2 nanotubes on the biocompatibility of 3D printed Cu-bearing TC4 alloy

3D printed titanium implants have gained substantial attention in the medical fields of bone tissue and dental implants. Surface modification of titanium implants such as TiO2 nanotubes (TNT) make up for the interaction between the surface of titanium implants and the surrounding tissues by providing nanoporous structures and hydrophilic surfaces. In this study, a 3D printed Cu-bearing Ti6Al4V (TC4) alloy with micro/nano-topographical was employed as material model to explore the role played by Cu2+ and nanostructure in the physical–chemical properties of the material, osteoblast toxicity. The role of Cu2+ and nanostructure on macrophage proliferation, polarization and oxidative stress without and with lipopolysaccharide (LPS) stimulation was also evaluated. Surface characterizations showed TNT significantly increased the roughness and surface hydrophilicity of TC4 alloy. TNT-TC4-5Cu exhibited excellent corrosion properties in the absence and presence of LPS. The in vitro tests with MC3T3-E1 cells demonstrated that the TNT-TC4-5Cu alloys showed the better cytocompatibility. Moreover, TNT-TC4-5Cu alloy can inhibit macrophage polarization and decreased ROS generation without and with LPS stimulation, thereby promoting the biocompatibility. In summary, the TNT-TC4-5Cu alloy promoted the proliferation and adhesion of osteoblasts and inhibited the inflammatory response of macrophages, which has great potential to benefit the future development of orthopedic applications.