A high-performance chitosan-grafted Cu(Ⅱ) coating improves endothelialization and mitigates the degradation of biodegradable magnesium alloy stents.

Abstract

As biodegradable scaffolds with great application potential, magnesium alloy stents face problems in terms of their fast degradation rate and dysendothelialization of larger meshes. The present solution strategy was to achieve proper and long-term release of Cu(Ⅱ) ions by preparing a chitosan-grafted Cu(Ⅱ) coating to promote the endothelialization process and then reduce the degradation rate of magnesium alloy stents by improving their service environment. In this work, the effects of a functional coating on the corrosion resistance, endothelialization and blood compatibility of AZ31 magnesium alloy stents were systematically studied in vitro, and the relevant function of the coated stent was verified by implantation into the rabbit carotid artery. The in vitro results showed that this coating could promote the endothelialization function and blood compatibility of magnesium alloy stents and could maintain adequate corrosion resistance. The in vivo results indicated that endothelization was achieved one week after the implantation of a magnesium alloy stent with a chitosan-grafted Cu(Ⅱ) coating in the animal carotid artery, and its degradation rate was reduced by 50 %. In addition, this coating could induce the transformation of macrophages into the anti-inflammatory type. Thus, the chitosan-grafted Cu(Ⅱ) coating has been proven to promote the endothelization of magnesium alloy stents, reduce their degradation rate and further inhibit intimal hyperplasia, indicating good application prospects.