Biocompatibility and corrosion resistance of drug coatings with different polymers for magnesium alloy cardiovascular stents

Recently, advances in enhancing corrosion properties through various techniques, and the clinical application of biodegradable cardiovascular stents made from magnesium (Mg) alloys face challenges to corrosion resistance, blood compatibility, and biocompatibility. Drug-eluting stents (DES) offer a solution to enhance the corrosion resistance of Mg alloys while simultaneously reducing the occurrence of restenosis. In this study, WE43 Mg alloy was pretreated using electropolishing technology, and different polymers (PEG and PLLA) were used as drug-polymer coatings for the Mg alloy. At the same time, PTX, an anticoagulant, was incorporated to achieve drug coating of different polymers on WE43 Mg alloy. The corrosion resistance of different polymer-drug coatings was assessed using a plasma solution. Furthermore, in vitro and in vivo tests were used to evaluate the blood biocompatibility of these coatings. The results indicated the PTX-PEG-coated WE43 Mg alloy exhibited the highest corrosion resistance and the most stable drug release profile among the tested coatings. Its hemolysis rate of 0.6 % was within the clinical requirements (<5 %). The incorporation of PEG prevents non-specific protein adsorption and nanoparticle aggregation, enhancing the surface hemocompatibility of WE43 Mg alloy. Therefore, the PTX-PEG coating shows promising potential for application in the development of drug-coated Mg alloy.