Improved corrosion resistance and cytocompatibility of Mg–Zn–Y–Nd alloy by the electrografted polycaprolactone coating

Abstract

Severe and non-uniform degradation of magnesium (Mg) alloys limits their general application in the field of vascular stents. Polymer coatings, which have been widely used in biodegradable materials, can simultaneously reduce degradation and improve the biocompatibility of Mg alloys. In this study, polycaprolactone (PCL) coating was prepared on Mg–Zn–Y–Nd alloy by electrografting. The microstructure of the prepared coating is significantly influenced by current density and monomer concentration, according to scanning electron microscope/energy dispersive spectroscopy results. The electrografted PCL coating has two molecular weights, 15.5 × 103 g·mol−1 and 1.08 × 103 g·mol−1, according to gel permeation chromatography results. Electrochemical and immersion tests show that the electrografted PCL coating has better anti-corrosion properties than the PCL coating prepared using the traditional dipping method. Meanwhile, human umbilical vein endothelial cells and smooth muscle cells culture results show that electrografted PCL coating improves the magnesium alloy’s ability to maintain cell viability. Furthermore, arginine-glycine-aspartic acid was fixed on the surface of the PCL coating to confirm the possibility of functionalisation of the electrografted PCL coating. The results show that the composite coating promotes cell adhesion.