CuO/Cu2O Coatings via Plasma Electrolytic Oxidation on Ti–4.5Cu Alloy: A Synergistic Approach to Antibacterial Properties and Cytocompatibility

In this article, plasma electrolytic oxidation (PEO) is applied to Ti–4.5Cu alloy to prepare a Cu₂O/CuO containing coating to improve the antimicrobial properties and cytocompatibility. Scanning electron microscopy and X-ray photoelectron spectroscopy are used to characterize the surface microstructure as well as the elemental valence states, and electrochemical tests and inductively coupled plasma spectroscopy are used to determine the corrosive properties and Cu-ion release behavior, and the antimicrobial properties are evaluated by plate counting method and the cytotoxicity is evaluated by methylthiazolyldiphenyl-tetrazolium bromide (MTT) method. In the results, it is shown that PEO treatment significantly improves the hardness, hydrophilicity, roughness, corrosion resistance, and accelerated Cu-ion release. In the plate counting method results, it is shown that the antimicrobial capacity of Ti–4.5Cu alloys is significantly increased to >99.9% after the PEO treatment due to multiple effects of the release of Cu ions and the formation of Cu₂O and CuO. Furthermore, PEO treatment promotes the proliferation of L929 cells while the surface morphology after sandblasting has a further value-added effect on cell adhesion. It is concluded that Cu ion and the surface morphology play a decisive role in the adhesion and proliferation of the cells.