Micro-arc oxidation treatment applied on the surface of β Ti[sbnd]Nb matrix composites as a strategy to modulate cellular behavior

Abstract

Large bone injuries require long-term implant materials with multifunctional properties. While β-type Ti[sbnd]Nb 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 Ti[sbnd]Nb matrices reinforced with TiC and/or TiB precipitates have recently demonstrated superior tribocorrosion resistance compared to unreinforced β Ti[sbnd]Nb 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.