Microarc oxidation-PBAT composite coating on EK30 biodegradable magnesium alloys to enhance corrosion resistance and
Weisheng Cao1, Siyu Zhu2, Weiqiang Wang1
1School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China.
Abstract:
The rapid degradation rate of biodegradable magnesium alloys restricts their use in medical implants. Therefore, designing a protective coating with a slow degradation rate and good biocompatibility is crucial. For biodegradable magnesium alloy stents, it is equally important to enhance the material's corrosion resistance and ensure the coating's deformation adaptability to the stent. This study, utilized a combination of micro-arc oxidation (MAO) and dip-coating techniques to develop a novel composite coating comprising an MAO base layer and a poly(butylene adipate-co-terephthalate) (PBAT) outer layer on EK30 magnesium alloy. This composite coating was designed to enhance the corrosion resistance and biocompatibility of EK30 magnesium alloy for stent applications. The surface characteristics, corrosion resistance, in vitro cytocompatibility, and deformation adaptability of the composite coating to the stent were evaluated. The MAO-PBAT composite coating demonstrated a low corrosion current density (Icorr = 2.381 ×10-8 A/cm2), three orders of magnitude lower than that of unmodified EK30 magnesium alloy. Live/dead cell staining results confirmed that the composite coating exhibited good cytocompatibility with human aortic endothelial cells (HAECs) and human aortic smooth muscle cells (HASMCs). Observations of the stent treated with the composite coating during crimping and expansion showed that the composite coating possessed excellent deformation adaptability. These results indicate that the MAO-PBAT composite coating has significant potential for vascular stent application.
