Biological and Corrosion Barrier Characteristics of Electrophoretically Obtained Zinc Oxide/Bioactive Glass Composite Coating on Treated AZ31 Mg Alloy: Toward Further In Vitro Study

In the present study, the corrosion barrier performance and biological properties of AZ31 magnesium substrate, previously treated by plasma electrolytic oxidation technique, were simultaneously improved by zinc oxide-bioactive glass (ZnO-BG) coating applied using the electrophoretic deposition technique. For this purpose, core–shell ZnO-BG nanoparticles were synthesized using a sonochemical/sol–gel procedure. According to our results, applying the ZnO-BG coating increased the total faradic resistance about 6 times compared to the oxidized substrate, while that was around 3 times by the ZnO coating. At long-term immersion, the CZnO coating revealed a higher barrier performance than ZnO coating, but both were less than the oxidized substrate. The water contact angle decreased remarkably by applying ZnO and ZnO-BG coatings on the oxide interlayer, which increased the wettability of the surface. The bone-like apatite formation was significantly higher for the ZnO-BG-coated specimen due to the release of Ca²⁺ ions from the bioactive glass nanoparticles. For the ZnO-BG-coated specimen, the ICP-OES analysis results displayed the lower Mg²⁺ concentration in the simulated body solution after 28 days, which confirmed the lower degradation of this specimen compared to the ZnO one. According to CellTiter-Blue® Cell test results, the MC3T3 cell viability was significantly improved on the ZnO-BG-coated specimen compared to other specimens.