Abstract

Magnesium (Mg) alloy has been actively investigated as a bioresorbable scaffold (BRS) for use as a next-generation stent because of its appropriate mechanical properties and biocompatibility. However, Mg alloy quickly degrades in the physiological environment. Hydrofluoric acid (HF) treatment and surface coating with biodegradable polymer are approaches for enhancing the corrosion resistance of Mg alloy. However, there are no studies that focus on the corrosion behavior of the Mg alloy stent after balloon catheter expansion, which results in mechanical stress and is required for stent placement. In this study, the corrosion behavior of a Mg alloy stent after expansion by a balloon catheter was investigated. Compared with the bare Mg alloy stent, the HF-treated Mg alloy stent showed excellent corrosion resistance without expansion. However, balloon catheter expansion caused small fragments and cracks to appear on the surface of the HF-treated Mg alloy stent and accelerated its corrosion rate. The HF-treated Mg alloy stent was therefore further coated with poly(d,l-lactic acid) (PDLLA). As a result, the high corrosion resistance of the coated stent was maintained after its expansion along with higher biocompatibility for endothelial cell adhesion than the stent without the polymer coating. The HF-treated and PDLLA-coated platform is expected to be a BRS candidate for clinical applications.

Graphic abstract

中文翻译：

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球囊膨胀后HF处理的Mg合金支架的耐腐蚀性及其可生物降解的聚合物涂层的改进

摘要

由于镁（Mg）合金具有适当的机械性能和生物相容性，因此已作为一种可生物吸收的支架（BRS）被积极研究用作下一代支架。然而，镁合金在生理环境中迅速降解。氢氟酸（HF）处理和可生物降解的聚合物表面涂层是增强Mg合金耐腐蚀性的方法。但是，没有研究集中在球囊导管扩张后镁合金支架的腐蚀行为上，这会导致机械应力，并且需要放置支架。在这项研究中，研究了镁合金支架通过球囊导管扩张后的腐蚀行为。与裸镁合金支架相比，经过HF处理的镁合金支架表现出出色的耐腐蚀性，且不会膨胀。然而，球囊导管的膨胀导致在经HF处理的Mg合金支架的表面上出现小碎片和裂纹，并加速了其腐蚀速度。因此，经HF处理的Mg合金支架进一步涂有聚（d，1-乳酸）（PDLLA）。结果，与没有聚合物涂层的支架相比，涂层的支架在膨胀后保持了高耐腐蚀性，并且具有更高的内皮细胞粘附生物相容性。经过HF处理和PDLLA涂层的平台有望成为临床应用的BRS候选产品。

图形摘要