一种无稀土和铝的镁基支架的降解行为及体内生物相容性

Degradation behaviors and in-vivo biocompatibility of a rare earth- and aluminum-free magnesium-based stent.

作者信息

Bian Dong, Zhou Xiaochen, Liu Jianing, Li Wenting, Shen Danni, Zheng Yufeng, Gu Wenda, Jiang Jingjun, Li Mei, Chu Xiao, Ma Limin, Wang Xiaolan, Zhang Yu, Leeflang Sander, Zhou Jie

机构信息

Department of Orthopedics, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, 510080, China.

Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing, 100871, China.

出版信息

Acta Biomater. 2021 Apr 1;124:382-397. doi: 10.1016/j.actbio.2021.01.031. Epub 2021 Jan 27.

Abstract

Biodegradable stents can provide scaffolding and anti-restenosis benefits in the short term and then gradually disappear over time to free the vessel, among which the Mg-based biodegradable metal stents have been prosperously developed. In the present study, a Mg-8.5Li (wt.%) alloy (RE- and Al-free) with high ductility (> 40%) was processed into mini-tubes, and further fabricated into finished stent through laser cutting and electropolishing. In-vitro degradation test was performed to evaluate the durability of this stent before and after balloon dilation. The influence of plastic deformation and residual stress (derived from the dilation process) on the degradation was checked with the assistance of finite element analysis. In addition, in-vivo degradation behaviors and biocompatibility of the stent were evaluated by performing implantation in iliac artery of minipigs. The balloon dilation process did not lead to deteriorated degradation, and this stent exhibited a decent degradation rate (0.15 mm/y) in vitro, but divergent result (> 0.6 mm/y) was found in vivo. The stent was almost completely degraded in 3 months, revealing an insufficient scaffolding time. Meanwhile, it did not induce possible thrombus, and it was tolerable by surrounding tissues in pigs. Besides, endothelial coverage in 1 month was achieved even under the severe degradation condition. In the end, the feasibility of this stent for treatment of benign vascular stenosis was generally discussed, and perspectives on future improvement of Mg-Li-based stents were proposed.

摘要

可生物降解支架可在短期内提供支架作用并具有抗再狭窄的益处,然后随着时间的推移逐渐消失以释放血管,其中镁基可生物降解金属支架已得到蓬勃发展。在本研究中,将一种具有高延展性(>40%)的Mg-8.5Li(重量%)合金(不含稀土元素和铝)加工成微型管,并通过激光切割和电解抛光进一步制成成品支架。进行体外降解试验以评估该支架在球囊扩张前后的耐久性。借助有限元分析检查塑性变形和残余应力(源自扩张过程)对降解的影响。此外,通过在小型猪的髂动脉中植入来评估支架的体内降解行为和生物相容性。球囊扩张过程并未导致降解恶化,该支架在体外表现出良好的降解速率(0.15毫米/年),但在体内发现了不同的结果(>0.6毫米/年)。该支架在3个月内几乎完全降解,显示出支架支撑时间不足。同时,它没有引发可能的血栓形成,并且猪的周围组织可以耐受。此外,即使在严重降解的情况下,1个月时也实现了内皮覆盖。最后,总体讨论了该支架治疗良性血管狭窄的可行性,并提出了未来改进镁锂基支架的展望。

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