ISSN   1004-0595

CN  62-1224/O4

高级检索

镍钛编织支架的磨屑特征与细胞毒性关系研究

Relationship Between Wear Debris Characteristics and Cytotoxicity for Nickel-Titanium Braided Stents

  • 摘要: 应用血管支架的介入性治疗方案已经成为治疗心血管疾病的重要手段,新型交叉编织血管支架具有灵活性和良好的轴向柔顺性,适用弯曲、分叉和承载等复杂支架应用场景要求,已经在临床推广使用. 生物医用镍钛合金(NiTi)因优异的生物相容性和形状记忆特性成为编织型支架的常用材料,支架在体内的摩擦磨损产生的磨屑会对人体的造成不良的生物学反应,对患者的生命健康产生严重威胁. 在此背景下,深入研究支架材料的磨损特性及其与生物体相互作用的关系,对于进一步优化支架设计、提高治疗效果至关重要. 为探究镍钛合金材料的磨屑特征与细胞毒性之间的映射关系,本文中开展了镍钛合金材料的体外摩擦磨损试验,采集不同磨损参数下的磨屑样本;研究了磨屑特征提取与智能识别算法,利用YOLOv5s和U-net卷积神经网络模型获取磨屑尺寸与形状类型的分布统计;此外,通过CCK-8染色法和活死细胞染色方法开展磨屑与细胞毒性试验,建立磨屑特征(磨屑尺寸与浓度)与细胞毒性的对应关系. 结果表明:不同工况下的磨屑均处于0~50 μm之间,0~10 μm磨屑占比均超过50%,磨屑尺寸分布在各个试验条件下呈正态分布;磨屑形状主要以不规则状为主,近球状磨屑占比最少;角度与摩擦次数均显著影响磨屑的尺寸与形状分布,24 400次和43 200次摩擦情况下尺寸分布较为相似,但与14 400次摩擦后的磨损磨屑差异较大,角度与磨屑分布呈现倒U形趋势,摩擦角在60°左右时出现极值点;润滑条件的改变显著增加了小尺寸和长条状磨屑的占比,大尺寸和近圆状磨屑占比有所降低. 细胞毒性试验结果显示,当磨屑浓度处于0~500 mg/ml区间时,细胞的毒性均为0或1级;随着磨屑样品浸提时间的增加,小尺寸(0~15 μm)磨屑浸提液的细胞增殖率虽有小幅度降低,但毒性等级仍为0和1级,符合生物医用材料细胞毒性标准,通过活死细胞图像可以看出所有细胞试验中细胞存活并且生长状况良好. 研究结果为镍钛合金编织支架的磨损特性和生物相容性研究提供依据,为编制支架的设计与性能提升提供参考.

     

    Abstract: The interventional treatment approach involving the application of vascular stents has become a crucial method in treating cardiovascular diseases. The novel cross-braided vascular stent exhibits flexibility and excellent axial pliability, catering to the demands of complex scenarios such as bending, branching, and load-bearing in clinical applications. It has been successfully introduced into clinical practice. Biomedical nickel-titanium (NiTi) alloy, owing to its exceptional biocompatibility and shape memory properties, has become a prevalent material for woven stent fabrication. The wear debris generated by the frictional wear of the stent within the human body can induce adverse biological responses, posing a serious threat to the life and health of the patients. In this context, a thorough investigation into the wear characteristics of stent materials and their interaction with the biological system was crucial for further optimizing stent designs and improving treatment outcomes. To explore the mapping relationship between the wear debris characteristics of NiTi alloy and cytotoxicity, this study conducted in vitro friction and wear experiments using NiTi alloy materials, collecting wear debris samples under different wear parameters. The study delved into wear debris feature extraction and intelligent recognition algorithms. Using the YOLOv5s and U-net convolutional neural network models to obtain distribution statistics of wear debris size and shape types. In addition, wear debris and cytotoxicity experiments were conducted using the Cell Counting Kit-8 (CCK-8) staining method and live-dead cell staining approach to establish the correlation between wear debris characteristics (size and concentration) and cytotoxicity. The results indicated that wear debris under different conditions ranged from 0 to 50 μm, with the proportion of 0~10 μm wear debris exceeding 50%. The size distribution of wear debris exhibited a normal distribution under various experimental conditions. The predominant shape of the wear debris was irregular, with near-spherical wear debris constituting the smallest proportion. Both angle and friction times significantly influenced the size and shape distribution of wear debris, with size distributions being relatively similar at 24 400 and 43 200 friction times, but differed significantly from the wear debris generated after 14 400 friction cycles. The relationship between angle and wear debris distribution exhibited an inverted U-shaped trend, with the friction angle reaching an extremum at around 60°. Changes in lubrication conditions notably increased the proportion of small-sized and elongated wear debris, while decreasing the proportion of large-sized and nearly circular wear debris. Cytotoxicity experiment results demonstrated that when the concentration of wear debris was within the range of 0~500 mg/mL, the cytotoxicity of the cells was graded as 0 or 1. With an increase in the immersion time of wear debris samples, the cell proliferation rate of small-sized wear debris (0~15 μm) leaching solution experienced a slight decrease. However, the toxicity level remained at grade 0 and 1, aligning with the cytotoxicity standards for biomedical materials. Live-dead cell images confirmed cell survival and a favorable growth condition. The research findings provided a foundation for the study of wear properties and biocompatibility of nickel-titanium alloy braided stents, offering valuable insights for the design and performance improvement of stents.

     

/

返回文章
返回