靶向捕获内皮祖细胞磁性纳米粒子的修饰及其功能评价

发布时间：2018-02-24 21:08

本文关键词： 内皮祖细胞磁性纳米粒子捕获铁支架　出处：《西南交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：在心血管支架介入治疗的过程中,有可能会导致支架内再狭窄和晚期血栓,影响治疗的安全性和长期疗效。过去的几十年里,研究者们已经采用多种改性技术来提高血管支架的生物相容性和血液相容性,血管支架经历多次变革,目前已发展到包括裸金属支架,药物洗脱支架,内皮祖细胞(EPCs)捕获支架,可降解金属支架和时序性功能支架在内的多种支架并存的时代。EPCs作为一种多能干细胞,能够定向分化成为内皮细胞,对于血管支架植入后损伤血管内皮细胞层的修复重建具有重要作用。构建EPCs捕获支架是目前心血管疾病治疗的一个研究热点。但是由于血液中EPCs数量较少和捕获特异性不强等原因,导致支架表面EPCs的数量不足从而限制了内皮化的进程。本论文用磁性纳米粒子特异性捕获血液中的EPCs,并且引入铁支架作为磁响应源,共同作用提高纳米粒子表面捕获率。首先采用共价接枝将CD34抗体修饰到双羧基PEG修饰的四氧化三铁磁性纳米粒子上,构建能够特异性识别EPCs的功能型磁性纳米粒子。通过红外检测、水合粒径分析、透射电镜等方法对修饰前后磁性纳米粒子的理化性质进行检测,通过将其与EPCs共混培养评价细胞活性,以及通过溶血率和部分凝血酶时间等血液学评价血液相容性。实验结果表明CD34抗体成功修饰到磁性纳米粒子表面,修饰后的纳米粒子在一定的浓度范围内能够促进细胞增殖,并且一定程度上延长血液的凝血时间。其次评价CD34抗体修饰后的磁性纳米粒子与EPCs短时间的识别效果及在外加磁场的作用下其对EPCs的捕获效果,结果表明Fe_3O_4-PEG@CD34纳米粒子短时间对EPCs具有较好的识别结合作用,并且能在外加磁场作用下初步实现在动态环境下对EPCs的捕获。最后开展了在外加磁场作用下该功能化纳米粒子在体内捕获EPCs并将其定向归巢到铁支架表面的情况。结果表明Fe_3O_4-PEG@CD34纳米粒子能够特异性识别捕获血液中的CD34阳性细胞,并且能在外加磁场的作用下将其迅速归巢到铁支架表面,这为后期实现支架表面快速内皮化提供了可能。
[Abstract]:In the course of interventional treatment of cardiovascular stents, it is possible to cause restenosis and late thrombosis in the stent, affecting the safety and long-term efficacy of the treatment. Researchers have used a variety of modified techniques to improve the biocompatibility and blood compatibility of vascular stents, which have undergone many changes, including bare metal stents, drug-eluting stents, and endothelial progenitor cells (EPCs) capture stents. As a kind of pluripotent stem cells, EPCs can be differentiated into endothelial cells as a kind of pluripotent stem cells. It plays an important role in the repair and reconstruction of vascular endothelial cell layer after vascular stent implantation. The construction of EPCs capture stent is a research hotspot in the treatment of cardiovascular disease at present. However, because of the low number and capture of EPCs in blood, it is a hot topic in the treatment of cardiovascular disease. Lack of specificity and other reasons, The lack of EPCs on the surface of the scaffold limits the process of endothelialization. In this paper, the magnetic nanoparticles were used to specifically capture the EPCs in the blood, and the iron scaffold was introduced as the magnetic response source. The covalent grafting of CD34 antibody onto the ferromagnetic nanoparticles modified by dicarboxylic PEG was used to improve the surface trapping efficiency of nanoparticles. The functional magnetic nanoparticles which can specifically recognize EPCs were constructed. The physical and chemical properties of magnetic nanoparticles before and after modification were detected by infrared detection, hydration particle size analysis and transmission electron microscopy. The cell activity was evaluated by mixing it with EPCs, and the blood compatibility was evaluated by hemolysis rate and partial thrombin time. The results showed that CD34 antibody was successfully modified to the surface of magnetic nanoparticles. The modified nanoparticles can promote cell proliferation in a certain concentration range. To some extent, the coagulation time of blood was prolonged. Secondly, the recognition effect of magnetic nanoparticles modified with CD34 antibody and EPCs for a short time and the capture effect of EPCs under the action of external magnetic field were evaluated. The results show that Fe_3O_4-PEG@CD34 nanoparticles have good recognition and binding to EPCs in short time. Finally, the functionalized nanoparticles can capture EPCs in vivo and homing it to the surface of the iron scaffold under the action of external magnetic field. The results showed that Fe_3O_4-PEG@CD34 nanoparticles could specifically identify CD34 positive cells in the captured blood. And it can quickly homing to the surface of iron scaffold under the action of external magnetic field, which makes it possible to realize the rapid endothelialization of the surface of the scaffold in the later stage.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R54;R318.08

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