Study on M2-type macrophage exosomes coated with S-HA to modify magnesium alloy surface for vascular scaffolds

Around the world, acute ischemic stroke (IS) is a major cause of mortality and acquired disability, one of the most popular and clinically successful treatments for cardiovascular and cerebrovascular disorders is stent intervention. The Mg-Zn-Y-Nd alloy (ZE21B magnesium alloy), which is biodegradable, offers good mechanical and biocompatibility qualities and a promising future in vascular stents. However, the magnesium alloy stent degrades too quickly after implantation, and issues with restenosis and inadequate endothelialization have made it impossible to use it further. In this study, the corrosion resistance of magnesium alloy samples was firstly enhanced by fluorination, followed by self-assembled polydopamine coating, and finally, Exo@S-HA core-shell structured nanoparticles were immobilized on the surface of the coating by ultrasonic spraying. First, exosome fluorescence labeling, AFM, XPS, and FT-IR were used to show that the MgF₂/PDA/Exo@S-HA composite coating was successfully prepared, and the good hydrophilicity of the composite coating was proved by the WCA, which is favorable for cell adhesion and proliferation. Subsequent tests on blood and cells demonstrated the beneficial biological properties of the composite coating, including anticoagulation, anti-inflammatory, anti-proliferation, and endothelial cell proliferation. In conclusion, the composite coating has potential applications in surface modification of cardiovascular biomaterials.