A polydopamine-based calcium phosphate/graphene oxide composite coating on magnesium alloy to improve corrosion resistance and biocompatibility for biomedical applications

Abstract

In order to improve the corrosion resistance and biocompatibility of magnesium (Mg) alloy and reduce the rapid degradation rate, which limits its biomedical application, a calcium phosphate (CaP)/graphene oxide (GO) composite coating based on polydopamine (PDA) was prepared. PDA was used as a pretreatment layer to induce biomimetic deposition of CaP, and then GO as a sealing layer was spin-coated with ethanol and water as dispersants, respectively. The composition, morphology, corrosion resistance and biocompatibility of the composite coating were characterized and tested. The result of electrochemical and immersion test shows that the corrosion resistance of the PDA/CaP/GO composite coating was significantly enhanced. Meanwhile, the in vitro cell experiments indicates that the composite coating promotes cell adhesion and improves biocompatibility. Moreover, the corrosion resistance and biocompatibility of the PDA/CaP/GO composite coating with water as the dispersant is better than that with ethanol, and is significantly improved compared with the Mg alloy, indicating the good potential for development in the biomedical field.