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) nanocomposite film was successfully applied to pure magnesium (Mg) surface using the 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 the desired corrosion resistance in simulated body fluid (SBF). However, the deposition of the top-layer PCL coating (utilizing 8wt% PCL) over the MgO-TiO2 nanocomposite coating greatly improved the corrosion resistance of the Mg substrate. The proposed PCL top-layer coated MgO-TiO2 nanocomposite film could be considered as a promising candidate for the surface modification of Mg-based biodegradable implants. Due to the microstructural and macrostructural porous nature of the PEO film, this coating can be further used on the surface of biodegradable implants not only to control the degradation rate but also to deliver therapeutic molecules.