A nano-structured TiO2/CuO/Cu2O coating on Ti-Cu alloy with dual function of antibacterial ability and osteogenic activity

Bacteria-associated infection and poor osseointegration are two main reasons for orthopedic implant failure. Ti-Cu alloy exhibited excellent antibacterial property, but still presented unsatisfied osteogenic activities. Therefore, Ti-Cu alloy was surface modified by an alkali-heat treatment in this paper to improve the osteogenic ability without reduction in antibacterial ability. A TiO2/CuO/Cu2O composite coating with nanostructure was deposited on Ti-Cu alloy. The coating showed increased roughness and great hydrophilicity. Antibacterial tests indicated that the modified Ti-Cu alloy exhibited stronger antibacterial ability against Staphylococcus aureus (S. aureus) than Ti-Cu alloy. Meanwhile, cell experiments demonstrated that the composite coating promoted initial adhesion and spreading of MC3T3-E1 cells, enhanced alkaline phosphatase (ALP) activities as well as extracellular matrix (ECM) mineralization, and significantly upregulated osteogenesis-related gene expressions. It was suggested that the nano-structured TiO2/CuO/Cu2O coating on Ti-Cu alloy might provide a potential strategy for orthopedic implant failure.