新型全降解镁合金气管支架的制备及性能评价

发布时间：2018-02-01 17:55

本文关键词： 镁合金全降解气管支架降解性能生物相容性　出处：《郑州大学》2017年硕士论文　论文类型：学位论文

【摘要】：近年来,气管狭窄引发的气管及支气管疾病呈现增多的趋势,众多治疗手段中,气管支架是非常有效的介入手段。临床常用支架因不可降解需进行二次取出手术,同时较差的生物相容性易产生肉芽增生导致气管再狭窄,给病人造成痛苦和负担。因此,新型全降解气管支架的研发作为治疗气管狭窄的新技术备受关注。本文选取实验室自主研发的Mg-Zn-Y-Nd合金微丝,采用单丝一体化整体性编织技术及菱形编织结构,并辅以100°C×10min的热处理工艺,制备新型全降解镁合金气管支架,支架直径8mm、长度20mm、网眼面积5mm~2,并采用拉伸测试、压缩测试、电化学实验、浸泡实验、扫描分析、失重分析和动物实验等手段,优选最优支架编织工艺,探讨支架体内和体外降解行为和生物相容性能。研究表明,对镁合金气管支架进行轴向拉伸性能和径向压缩性能测试,直径0.16mm、0.20mm、0.24mm、0.28mm微丝编织的支架抗拉强度分别为107MPa、193MPa、252MPa、310MPa,延伸率分别为35%、32%、49%、43%;压缩强力分别为84c N、173cN、330cN、552cN,回弹率分别为87.3%、85.4%、84.6%、79.2%。同时对比商用Ni-Ti合金支架的力学性能,直径0.24mm微丝编织支架的力学性能与Ni-Ti合金支架接近。对不同状态镁合金气管支架在模拟气道环境(GS)中的浸泡4周发现:未退火态支架的平均降解速率为0.3085mm/y,退火态为0.0736mm/y。未退火态支架在降解过程中有裂纹出现,退火态支架在浸泡4周后依然保持完成的结构,降解性能良好。退火态支架的降解行为如下:(i)在丝材搭接处,降解主要以局部的点蚀向外扩展,随着时间的延长发展为全面降解,支架优先在此部位发生断裂;(ii)在支架的其它区域,降解过程以均匀的点蚀为主,点蚀坑小且浅,向四周扩展形成均匀降解。通过球囊扩张技术将镁合金气管支架植入实验兔气管内,探究支架在体内的降解性能和生物相容性能。结果表明,支架植入体内4周时的平均降解速率为0.5536 mm/y,在动物体内的降解速率稍快于在体外GS中的降解速率。X射线观察、CT显影、气管组织解剖及病理切片检测发现:镁合金气管支架植入体内膨胀良好,4周后完全降解,气管组织未出现肉芽增生及明显炎症,未发生结构性病变,气管上皮细胞生长良好,说明镁合金支架具有良好的体内生物相容性。血液和尿液镁离子浓度检测及脏器病理切片观察结果显示:支架植入后,未造成血液和尿液中离子浓度显著变化,未引起心、肝、脾、肾等重要脏器发生病变,说明镁合金支架具有良好的生物安全性。
[Abstract]:In recent years, tracheal stenosis caused by trachea and bronchial diseases show an increasing trend, many treatment methods. Tracheal stent is a very effective interventional method. Because of non-degradable stents need to be removed for a second time, and poor biocompatibility is prone to granulation proliferation, resulting in tracheal restenosis. Therefore, the research and development of new fully degradable tracheal stent as a new technology for the treatment of trachea stenosis has attracted much attention. In this paper, Mg-Zn-Y-Nd alloy microwires developed by our laboratory are selected. A new type of fully degradable magnesium alloy tracheal scaffold was prepared by using monofilament integrated braiding technique and diamond braiding structure and heat treatment process of 100 掳C 脳 10 min. The diameter of the scaffold was 8 mm. The length was 20mm, the mesh area was 5mm / 2, and the optimum braiding technology was selected by means of tensile test, compression test, electrochemical test, immersion test, scanning analysis, weightlessness analysis and animal experiment. The degradation behavior and biocompatibility of magnesium alloy trachea scaffolds in vivo and in vitro were investigated. The axial tensile properties and radial compression properties of magnesium alloy trachea scaffolds were measured and the diameter of the scaffolds was 0.16mm / 0.20mm. The tensile strength of 0.24mm / 0.28mm microfilament braided scaffold was 107MPA ~ (193) MPA ~ (252MPa) ~ (310MPa), and the elongation was 350.32% respectively. 49 and 43; The compression strength is 84c Nu 173cN 330cN 552 CN, and the springback rate is 87.3% 85.4cN, 84.6% respectively. At the same time, the mechanical properties of commercial Ni-Ti alloy scaffolds were compared. The mechanical properties of 0.24mm microfilament braided scaffold were similar to those of Ni-Ti alloy scaffold. It was found that the average degradation rate of unannealed scaffolds was 0.3085mm / y after immersion for 4 weeks. The annealed state was 0.0736mm / y. there were cracks in the unannealed scaffold during the degradation, and the annealed scaffold remained the finished structure after 4 weeks of immersion. The degradation behavior of the annealed scaffold is as follows: 1. The degradation behavior of the annealed scaffold is as follows: (1) at the place where the wire is overlapped, the degradation mainly extends outward by local pitting corrosion, and develops into a total degradation with the extension of time. The fracture of the scaffold occurred in this area. In other regions of the scaffold, the degradation process was mainly pitting corrosion, the pitting pit was small and shallow, and it spread around to form a uniform degradation. The magnesium alloy tracheal stent was implanted into the trachea of the experimental rabbit by balloon expansion technique. The biodegradability and biocompatibility of the scaffolds were investigated. The results showed that the average degradation rate was 0. 5536 mm/y after 4 weeks of stent implantation. The degradation rate in animals was a little faster than that in GS in vitro. Ct imaging was observed. The trachea tissue anatomy and pathological sections showed that magnesium alloy trachea stent implantation had good expansion in vivo. After 4 weeks of complete degradation, there was no granulation proliferation and obvious inflammation in tracheal tissue, no structural lesions occurred, and the epithelial cells of trachea grew well. It showed that magnesium alloy scaffold had good biocompatibility in vivo. The results of magnesium ion concentration in blood and urine and pathological sections of viscera showed that there was no significant change of ion concentration in blood and urine after stent implantation. No pathological changes were found in heart, liver, spleen, kidney and other important organs, indicating that magnesium alloy scaffold has good biological safety.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG146.22;R318.08

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