Physicochemical properties and in vitro cytocompatibility of modified titanium surfaces prepared via micro-arc oxidation with different calcium concentrations

Objective To explore the effect of calcium concentration in the electrolyte solution on the physicochemical properties and biocompatibility of coatings formed by micro-arc oxidation (MAO) on titanium surfaces. Methods The surfaces of pure titanium plates were modified by MAO in an electrolytic solution containing calcium acetate (CA; C ₄ H ₆ CaO ₄ ) at concentrations of 0.05, 0.1, 0.2, or 0.3 M and β-glycerophosphate disodium salt pentahydrate (β-GP; C ₃ H ₇ Na ₂ O ₆ P·5H ₂ O) at a fixed concentration of 0.02 M. Surface topography, elemental characteristics, phase composition, and roughness were investigated by scanning electron microscopy, energy-dispersive X-ray analysis, X-ray diffraction, and a surface roughness tester, respectively. To assess the cytocompatibility and osteoinductivity of the surfaces, MC3T3-E1 preosteoblasts were cultured on the surfaces in vitro, and cell morphology, adhesion, proliferation, and differentiation were observed. Results The porous MAO coating was composed primarily of TiO ₂ rutile and anatase. The amount of TiO ₂ rutile, the Ca/P ratio, and the surface roughness of the MAO coating increased with increasing CA concentration in the electrolyte solution. Ca ₃ (PO ₄ ) ₂ , CaCO ₃ , and CaTiO ₃ were formed on MAO-treated surfaces prepared with CA concentrations of 0.2 and 0.3 M. Cell proliferation and differentiation increased with increasing CA concentration, with MC3T3-E1 cells exhibiting favorable morphologies for bone-implant integration. Conclusions MAO coating improves the surface characteristics and cytocompatibility of titanium for osseointegration. Higher CA concentration in the MAO electrolyte solution has a positive effect on the surface properties, chemical composition, and cell response.