Synthesizing a multifunctional polymer to construct the catalytically NO-generating coating for improving corrosion resistance and biocompatibility of the magnesium alloy stent materials

Abstract

Owing to its excellent mechanical properties and biodegradability, magnesium-based alloys have become the research focus of biodegradable cardiovascular materials. However, the in vivo rapid degradation and poor surface endothelial regeneration and repair ability still restrict their clinical applications in the field of vascular stent materials. Nitric oxide (NO), as an endogenous gas signaling molecule, has multiple effects such as anticoagulation, promoting endothelialization, and anti-restenosis, showing a great potential for improving the performances of the cardiovascular materials and devices. In the present study, based on six-arm polyethylene glycol (PEG), a novel anticoagulant polymer (PEG-Hep-SeCA) with the catalytic release of NO was synthesized by successively introducing heparin and selenocystamine, followed by the immobilization of the as-synthesized polymer on the Zn2+-loaded polydopamine coating modified magnesium alloy surface to enhance the anti-corrosion and biocompatibility. The results demonstrated that the PEG-Hep-SeCA polymer coating was uniform and dense, which could not only obviously enhance the anticorrosion and the hydrophilicity of the magnesium alloy, but also selectively promote the bovine serum albumin (BSA) adsorption, thereby significantly improving the endothelial cells (ECs) growth and hemocompatibility. Additionally, the as-prepared polymer coating could effectively catalyze the release of NO from endogenous NO donors, which can further ameliorate the hemocompatibility and ECs growth, as well as enhance the expression of vascular endothelial cell growth factor (VEGF) and NO of the ECs. Therefore, this study opens a new way to construct the multifunctional coating with the ability of catalytic releasing NO on the surfaces of the magnesium-based alloys to simultaneously reduce the corrosion speed, improve the hemocompatibility, and accelerate the reendothelialization.