An asymmetric surface coating strategy for improved corrosion resistance and vascular compatibility of magnesium alloy stents. (November 2020)

• Record Type: Journal Article
• Authors: Kang, Min-Ho; Cheon, Kwang-Hee; Jo, Kyung-Il; Ahn, Ji-Ho; Kim, Hyoun-Ee; Jung, Hyun-Do; Jang, Tae-Sik
• Is Part Of: Materials & design. Volume 196(2020)
• Publication Date: 2020-11
• Subjects: Magnesium -- Asymmetric coating -- Corrosion resistance -- Biocompatibility -- Poly(ether imide) -- Poly(lactic-co-glycolic acid); Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2020.109182
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: Magnesium (Mg) and its alloys are promising materials for biodegradable drug-eluting stent applications, but their rapid corrosion remains a major challenge for clinical practice. Considerable efforts have been made to develop an efficient surface coating that can provide higher Mg stent corrosion resistance, sustained drug-delivery capability, and vascular compatibility. Herein, we introduce poly(ether imide) (PEI) and poly(lactic- co -glycolic acid) (PLGA) as surface coating polymers for WE43 Mg-alloy stent. Using a sequential spray-coating method, we developed a novel asymmetric stent coating comprising an inner surface coated with a PEI single layer and outer/side surfaces coated with sirolimus-loaded PLGA/PEI double layers. PEI coating layer has excellent adhesiveness to WE43 surface and considerably improves WE43 corrosion resistance and in vitro endothelial cell compatibility. PLGA/PEI double coating layer ensures a low release rate of sirolimus and stable surface morphology during drug-release process. Only vascular smooth muscle cells are directly affected by sirolimus owing to the asymmetric geometry of PLGA/PEI double coating, which has a satisfactory anti-proliferation effect. These results indicate that the developed asymmetrically PEI- and PLGA/PEI-coated WE43 stents have significant potential for achieving enhanced re-endothelialization and suppressed in-stent restenosis in vascular stent applications. Graphical abstract: Unlabelled Image Highlights: An asymmetric surface coating was formed on magnesium-alloy stent forming different layers on luminal and abluminal surfaces. The poly(ether imide) coating layer effectively lowers the corrosion rate of the stent. Sirolimus incorporated in poly(lactic-co-glycolic acid) coating layer showed a stable release behavior. The poly(ether imide) coating on luminal surface significantly improved in vitro vascular compatibility. Sirolimus loaded poly(lactic-co-glycolic acid)/poly(ether imide) coating on abluminal surface suppressed restenosis response.