Li Ming, Xu Xuchen, Jia Zhaojun, Shi Yuying, Cheng Yan, Zheng Yufeng
Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China.
J Mater Chem B. 2017 Feb 14;5(6):1182-1194. doi: 10.1039/c6tb02634f. Epub 2017 Jan 20.
Iron and its alloys can be potentially employed to fabricate advanced degradable cardiovascular stents due to their excellent mechanical and biocompatibility properties. However, their clinical applications are hindered by their inherent slow degradation rate, the formation of thrombosis and in-stent restenosis. In this study, vertically oriented and orderly arranged α-FeO (hematite) nanotubes with diameters ranging from 30 nm to 70 nm were successfully fabricated on iron substrates using an anodic oxidation approach. These nanotubular coatings acted as drug depots by being loaded with anti-proliferation drug rapamycin to accelerate the re-endothelialization process and being coated by PLGA through a simple spin-coating process to control the drug release rate. The static immersion test showed that the 50 nm-FeO nanotube arrays displayed a faster corrosion rate than pristine Fe, and the PLGA coating effectively reduced the initial burst release of the loaded drug and extended the rapamycin release time to 30 days. The CCK-8 assay and immunofluorescence staining analysis results indicated that the endothelial cells (ECs) on the coated samples showed higher cell viability than the vascular smooth muscle cells (VSMCs), with possible outcomes to promote re-endothelialization and decrease VSMC proliferation. In addition, the surface modified iron exhibited very good hemocompatibility. The current findings suggested that fabricating rapamycin-loaded and PLGA coated FeO nanotubes on a pure iron surface may be a promising method to improve the corrosion rate and accelerate the re-endothelialization of the iron for biodegradable cardiovascular stent applications.
铁及其合金因其优异的机械性能和生物相容性，有潜力用于制造先进的可降解心血管支架。然而，其临床应用受到固有降解速度慢、血栓形成和支架内再狭窄的阻碍。在本研究中，采用阳极氧化法在铁基底上成功制备了直径为30纳米至70纳米的垂直取向且有序排列的α-FeO（赤铁矿）纳米管。这些纳米管涂层通过负载抗增殖药物雷帕霉素作为药物储存库，以加速再内皮化过程，并通过简单的旋涂工艺用聚乳酸-羟基乙酸共聚物（PLGA）进行包覆，以控制药物释放速率。静态浸泡试验表明，50纳米的FeO纳米管阵列显示出比原始铁更快的腐蚀速率，并且PLGA涂层有效地减少了负载药物的初始突释，并将雷帕霉素的释放时间延长至30天。细胞计数试剂盒-8（CCK-8）检测和免疫荧光染色分析结果表明，涂层样品上的内皮细胞（ECs）比血管平滑肌细胞（VSMCs）具有更高的细胞活力，可能会促进再内皮化并减少VSMC增殖。此外，表面改性的铁表现出非常好的血液相容性。目前的研究结果表明，在纯铁表面制备负载雷帕霉素和PLGA包覆的FeO纳米管可能是一种有前景的方法，可提高铁的腐蚀速率并加速其在可降解心血管支架应用中的再内皮化。
