Enhancement of corrosion resistance and biocompatibility of Mg-Nd-Zn-Zr alloy achieved with phosphate coating for vascular stent application

We have developed a convenient chemical conversion method of preparing a Mg-3(PO4)(2) coating with a lamellar structure of about 1-5 mu m width on Mg-Nd-Zn-Zr (denoted as JDBM) alloy, aiming to improve the corrosion resistance and biological response. The protective effect of the phosphate coating on JDBM alloy leads to an increase in corrosion resistance of about 25% from 0.337 +/- 0.021 to 0.253 +/- 0.047 mm y(-1). A systematic study on in vitro cytocompatibility test shows that the phosphate coated JDBM has minimal negative effect on human umbilical vein endothelial cells (HUVECs) viability, growth and proliferation, and the coating also presents a favorable affinity for HUVECs by supporting higher adherent cell density and sufficient cell spreading. In addition, the investigation of in vitro hemocompatibility confirms reduced hemolysis ratio and excellent anti -platelet adhesion property of the phosphate coated JDBM. Furthermore, this study also presents our more recent efforts to develop an in-depth understanding of the mechanism which is involving anti-platelet adhesion on the surface of biodegradable Mg substrate. (C) 2020 The Author(s). Published by Elsevier B.V.