Micro-arc oxidation treatment applied on the surface of β TiNb matrix composites as a strategy to modulate cellular behavior

Abstract

Large bone injuries require long-term implant materials with multifunctional properties. While β-type TiNb alloys offer a reduced elastic modulus closer to bone stiffness, metallic materials remain susceptible to degradation under friction in corrosive environments, such as articulating joints exposed to body fluids. In this context, Ti-based matrix composites (TMCs) have emerged as promising alternatives, as β TiNb matrices reinforced with TiC and/or TiB precipitates have recently demonstrated superior tribocorrosion resistance compared to unreinforced β TiNb alloys, while maintaining low elastic moduli. The current study focuses on enhancing the biological properties of β-TMCs through surface micro-arc oxidation (MAO) treatment. An electrolyte enriched with Ca-, P-, and Mg-based compounds was used to generate bioactive porous oxide coatings. X-ray photoelectron spectroscopy (XPS) revealed Ca/P ratios close to 1.67 in all MAO coatings, while high-resolution spectra identified phosphate functional groups and calcium carbonate, indicating favorable compositions for bone regeneration. TiB and TiC may have formed volatile oxides such as B₂O₃ and CO₂, whereas only B₂O₃ was detected in the XPS results. Furthermore, TiB in the substrate refined pore sizes to below 1 μm² and increased MAO coating thickness to over 11 μm, although neither TiB nor TiC affected the anatase-to-rutile ratio. In vitro cellular assays demonstrated that MAO-treated β-TMCs facilitate osteoblast proliferation due to their controlled porous surface structure and biomimetic composition. These findings support β-TMCs as promising candidates for biomedical applications, with MAO treatment serving as an effective strategy for enhancing biological performance. Further preclinical studies are required to validate their clinical potential.