Control of surface composition and microstructure of nano super-hydrophilic TiO2-CuOy coatings through reactive sputtering to improve antibacterial ability, corrosion resistance, and biocompatibility

Abstract

In this work, the TiO2-CuOy antibacterial superhydrophilic nano-coating succeeded to be prepared on titanium sheet via the reactive magnetron sputtering, influence of oxygen content on the surface morphology, phase composition and structure of TiO2-CuOy coatings were investigated, the bonding of TiO2-CuO system to O2 molecule in TiO2-CuO-O2 systems was simulated through molecular dynamics, and the corresponding antibacterial, biological and physical properties were also studied. Results showed that CuOy transformed from Cu to Cu2O to CuO as the oxygen increased from 0% to50%, TiO2-CuOy coatings consisted of nano-grains, the surface roughness showed a decline trend with decreased grain size, it was consistent with the simulation result in TiO2-CuO-O2 system. After being irradiated under UV, TiO2-CuOy coatings became super-hydrophilic, which obtained enhanced properties in anti-bacteria, cytocompatibility and corrosion resistance. Owing to smaller grain size and surface roughness, higher copper ions releasing amount, CuOy either in Cu2O or CuO type performed better compared to normal nano-copper, in which TiO2-Cu2O coating was nontoxic and significantly promoted MC3T3-E1 cells proliferation, especially its antibacterial rate reached 99.985% to S.aureus under 2 h direct contact, which was able to prevent the infections occurring at the operation site in the early implantation.