钛表面固定特异性识别内皮祖细胞多肽适配子的研究

发布时间：2018-05-01 07:32

本文选题：多肽适配子 + 内皮祖细胞　；参考：《西南交通大学》2012年硕士论文

【摘要】：增生和再狭窄是血管支架临床植入后失败的最主要原因,心血管植入材料表面的快速内皮化是避免增生和再狭窄的有效方法之一。已有报道指出血管内内皮祖细胞的归巢对血管重新内皮化具有重大影响。在本论文中,在钛表面固定特异性识别和结合循环血液中的内皮祖细胞(EPC)的多肽适配子,构建内皮祖细胞的特异性识别表面,用于心血管材料的表面改性。首先,采用固相合成法合成与EPC具有特异性结合的多肽适配子,其序列为TPSLEQRTVYAK,并在羧基端进行生物素修饰。然后,通过层层自组装的方法将多肽适配子固定在钛材料表面。已有报道中指出,牛血清白蛋白(BSA)可以用于生物材料改性从而提高与血液接触材料的血液相容性。为了同时提高材料的血液相容性及捕获内皮祖细胞的能力,在层层自组装多肽适配子的过程中,也将BSA固定在了材料表面。采用石英晶体微天平(QCM),扫描电子显微镜(SEM), X射线光电子能谱仪(XPS),接触角测试仪等跟踪层层自组装的过程,对材料进行表征。血液试验结果表明,固定了牛血清白蛋白的材料表面,能够有效抑制纤维蛋白原粘附,降低纤维蛋白原激活程度,从而减少材料表面血小板的粘附数量,起到了一定的抗凝作用。内皮祖细胞体外静态实验结果表明,在钛表面通过自组装固定多肽适配子形成的生物修饰层有利于捕获内皮祖细胞,并对内皮祖细胞的粘附、生长与增殖有良好的促进作用。动物体内实验结果表明,固定多肽适配子材料表面形成了类似天然血管内膜的细胞层。机理研究表明,自组装生物修饰层钛表面有利于捕获循环血液中的内皮祖细胞,并且降低血小板的粘附数量以及激活程度,从而提高材料的血液相容性。本文提供了一种在金属材料表面固定多肽适配子的有效方法,并且对固定多肽适配子的材料进行了系统的生物学评价。体外研究证明固定了多肽适配子的材料比未改性的纯钛材料具有更优异的血液相容性,更利于EPC的粘附和增殖。动物试验结果表明,固定多肽适配子的材料表面形成了血管内膜组织。
[Abstract]:Proliferation and restenosis are the main causes of failure after stent implantation. Rapid endothelialization of cardiovascular implant surface is one of the effective methods to avoid proliferation and restenosis. It has been reported that homing of endothelial progenitor cells in blood vessels has a significant effect on vascular re-endothelialization. In this thesis, the specific recognition surface of endothelial progenitor cells (EPC) was constructed by immobilization of titanium on the surface of titanium and binding to the polypeptide adaptor of endothelial progenitor cells (EPCs) in circulating blood for surface modification of cardiovascular materials. Firstly, a peptide aptamer with specific binding to EPC was synthesized by solid phase synthesis. The sequence of the aptamer was TPSLEQRTVYAKand modified with biotin at the carboxyl terminal. Then, polypeptide aptamers were immobilized on the surface of titanium by layer-by-layer self-assembly. It has been reported that bovine serum albumin (BSA) can be used to modify biomaterials and improve the blood compatibility with blood contact materials. In order to improve the blood compatibility of the material and the ability to capture endothelial progenitor cells, BSA was also immobilized on the surface of the material during the self-assembly of polypeptide aptamers. The materials were characterized by using quartz crystal microbalance QCM, scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and contact angle tester. The results of blood test showed that the surface of bovine serum albumin could effectively inhibit fibrinogen adhesion and reduce the degree of fibrinogen activation, thus reducing the number of platelet adhesion on the surface of the material. Played a certain anticoagulant effect. The results of static experiments in vitro showed that the biosynthesis layer formed by self-assembled aptamer of polypeptide on titanium surface was beneficial to capture endothelial progenitor cells, and could promote the adhesion, growth and proliferation of endothelial progenitor cells. The results of animal experiments in vivo showed that the aptamer of fixed polypeptide formed a cell layer similar to the natural vascular intima on the surface of the aptamer. The mechanism study shows that the self-assembled biomodified titanium surface is beneficial to capture endothelial progenitor cells in circulating blood and reduce the adhesion and activation of platelets so as to improve the blood compatibility of the materials. In this paper, an effective method for immobilization of polypeptide adaptors on the surface of metal materials is presented, and a systematic biological evaluation of the aptamers of fixed peptides is carried out. In vitro studies showed that the immobilized aptamer of polypeptide had better blood compatibility than unmodified pure titanium, and was more conducive to the adhesion and proliferation of EPC. The results of animal experiments showed that endovascular tissue was formed on the surface of the aptamer.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R318.08

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