Synthesis, microstructure and biodegradation behavior of MgO-TiO2-PCL nanocomposite coatings on the surface of magnesium-based biomaterials

Abstract In this study, a magnesium oxide - titanium dioxide (MgO-TiO2) composite coating was successfully applied to the surface of magnesium-based implants by a plasma electrolytic oxidation (PEO) technique in an electrolyte solution containing TiO2 nanoparticles. A uniform top-layer polycaprolactone (PCL) coating was eventually formed on the PEO-treated Mg through a dip-coating process. The results indicated that the porous nature of the PEO-coated samples could not provide desired corrosion resistance in simulated body fluid (SBF). However, the deposition of the top-layer PCL coating (utilizing 8 wt.% PCL) over the MgO-TiO2 composite coating greatly improved the corrosion resistance of Mg-based implants. The proposed PCL top-layer coated MgO-TiO2 composite coating could be considered as a promising candidate for the modification of Mg-based biodegradable implants. This coating can be further used on biodegradable implants to not only protect and control the degradation rate but also to locally deliver therapeutic molecules due to the microstructural and macrostructural porous nature.