Wang Pei, Liu Jing, Shen Shi, Li Qiyao, Luo Xujiang, Xiong Pan, Gao Shuang, Yan Jianglong, Cheng Yan, Xi Tingfei
Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China.
Tianjin Key Laboratory of Biomaterial Research, Institute of Biomedical Engineering, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300192, China.
ACS Biomater Sci Eng. 2019 Jul 8;5(7):3279-3292. doi: 10.1021/acsbiomaterials.9b00140. Epub 2019 Jun 20.
Bioabsorbable magnesium alloys are becoming prominent materials for cardiovascular stents, as their desirable mechanical properties and favorable biosafety. However, the rapid corrosion of magnesium alloys under physiological conditions hinders their wider application as medical implant materials. Fluoride chemical conversion treatment is an effective and simple technique to improve the corrosion resistance for magnesium alloys. Despite previous literature reporting on fluoride chemical conversion treatment with hydrofluoric acid (HF) in different conditions, some defects are still present on the surface of the coating. In this study, we report on a two-step alkali-fluoride treatment of magnesium alloy by effectively removing the second phase in the substrate surface and form a dense and flawless magnesium fluoride (MgF) coating to endow the magnesium alloy greater corrosion resistance. The results showed that the serious pitting corrosion caused by galvanic corrosion could be effectively prevented after removing of the second phase of the surface. In vivo tests in a rat subcutaneous implantation model showed that two-step alkali-fluoride-treated MgZnYNd alloy (MgZnYNd-A-F) uniformly corroded with a low corrosion rate. No subcutaneous gas cavities or significant inflammatory cell infiltration were observed for MgZnYNd-A-F in in vivo tests. The two-step alkali-fluoride treatment can significantly improve the corrosion resistance and biocompatibility of magnesium alloy, which has great potential in the application of vascular stents because of its simplicity and effectiveness.
生物可吸收镁合金正成为心血管支架的重要材料，因为它们具有理想的机械性能和良好的生物安全性。然而，镁合金在生理条件下的快速腐蚀阻碍了它们作为医用植入材料的更广泛应用。氟化物化学转化处理是一种有效且简单的提高镁合金耐腐蚀性的技术。尽管先前的文献报道了在不同条件下用氢氟酸（HF）进行氟化物化学转化处理，但涂层表面仍存在一些缺陷。在本研究中，我们报道了一种对镁合金进行两步碱 - 氟处理的方法，通过有效去除基体表面的第二相并形成致密无缺陷的氟化镁（MgF）涂层，赋予镁合金更高的耐腐蚀性。结果表明，去除表面第二相后，可有效防止电偶腐蚀引起的严重点蚀。在大鼠皮下植入模型中的体内试验表明，两步碱 - 氟处理的MgZnYNd合金（MgZnYNd - A - F）以低腐蚀速率均匀腐蚀。在体内试验中，未观察到MgZnYNd - A - F有皮下气腔或明显的炎性细胞浸润。两步碱 - 氟处理可显著提高镁合金的耐腐蚀性和生物相容性，因其简单有效，在血管支架应用中具有巨大潜力。
