Preparation of anticorrosion, biocompatible and antibacterial dicalcium phosphate dihydrate/polycaprolactone-titania composite coating on Mg alloy

As a new implantable biomaterial, magnesium (Mg) alloy has a broad application prospect. However, it is urgent to solve the disadvantage of rapid degradation. In this work, a composite coating with flaky dicalcium phosphate dihydrate (DCPD) as the bottom layer and polycaprolactone (PCL) incorporated with titania (TiO2) as the sealing layer was synthesized by electrodeposition and spin coating. Due to the sealing effect of the PCL layer and the blocking effect of TiO2 nanoparticles on the corrosive solution, the corrosion resistance of the composite coating sample is significantly improved, and its impedance could reach 628 times that of Mg alloy, and the total hydrogen evolution amount of the composite coating is only 1/19 of that of Mg alloy after immersion for 14 days. Besides, the addition of TiO2 not only further improved the biocompatibility of the sample, but also endowed it with excellent bacteriostasis, which was expected to meet the standard of clinical implantation.