A promoting nitric oxide‐releasing coating containing copper ion on ZE21B alloy for potential vascular stent application

Magnesium-based biodegradable metals as cardiovascular stents have shown a lot of excellent performance, which have been used to treat coronary artery diseases. However, the excessive degradation rate, imperfect biocompatibility and delayed re-endothelialization still lead to a considerable challenge for its application. In this work, to overcome these shortcomings, a compound of catalyzing nitric oxide (NO) generation containing copper ions (Cu2+) and hyaluronic acid (HA), an important component of the extracellular matrix, were covalently immobilized on a hydrofluoric acid (HF)-pretreated ZE21B alloy via amination layer for improving its corrosion resistance and endothelialization. Specifically, the Cu2+chelated firmly with a cyclen 1,4,7,10-tetraazacyclododecane-N, N′, N″, N″′- tetraacetic acid (DOTA) could form a stability of hybrid coating, avoiding the explosion of Cu2+. The chelated Cu2+enabled the catalytic generation of NO and promoted the adhesion and proliferation of endothelial cells (ECs) in vascular micro-environment. In this case, the synergistic effect of NO-generation and endothelial glycocalyx molecules of HA lead to efficient ECs promotion and smooth muscle cells (SMCs) inhibition. Meanwhile, the blood compatibility also had achieved a marked improvement. Moreover, the standard electrochemical measurements indicated that the functionalized ZE21B alloy had better anti-corrosion ability. In a conclusion, the dual-functional coating displays a great potential in the field of biodegradable magnesium-based implantable cardiovascular stents.