Enhanced corrosion resistance and biocompatibility of polydopamine/dicalcium phosphate dihydrate/collagen composite coating on magnesium alloy for orthopedic applications

Magnesium (Mg) and its alloys have been suggested as a promising next-generation orthopedic implant material. However, fast degradation in the physiological environment and potential cytotoxicity hinder their further clinic application. To enhance the biocorrosion resistance and cytocompatibility of Mg alloys, a multifunctional composite coating composed of polydopamine (PDA), dicalcium phosphate dihydrate (DCPD), collagen (Col) was prepared by a two-step chemical method. The surface morphology, chemical composition, thickness, corrosion performance, and cytotoxicity of the coating were investigated. The results showed that the PDA/DCPD/Col coating significantly improved the biocorrosion resistance and biomineralization ability of Mg alloys. Moreover, the PDA/DCPD/Col coating has a similar composition to natural bone, providing a more favorable interface for cell viability and adhesion. The PDA/DCPD/Col coating greatly enhanced the cytocompatibility and osteogenic differentiation ability compared with Mg alloy and PDA/DCPD coating. With enhanced cytocompatibility, osteogenic differentiation ability and corrosion resistance, the PDA/DCPD/Col composite coating exhibits great potential in bone tissue engineering. (C) 2019 Elsevier B.V. All rights reserved.