功能化纳米氧化石墨烯的制备及其肿瘤靶向性核素及光学分子影像

发布时间：2018-05-06 18:38

本文选题：纳米氧化石墨烯 + 肿瘤　；参考：《上海师范大学》2015年硕士论文

【摘要】：纳米氧化石墨烯,即石墨烯的氧化衍生物,作为一种新型二维的碳纳米材料,具有超大的比表面积和优异的光热效果等性质,已成为纳米医学领域中备受关注的研究热点。纳米氧化石墨烯含有大量的活性化学基团,比如羧基、羰基、羟基和环氧基等,既容易对其进行生物化学功能化,又使其具有很好的生物相容性,因此在生物医学领域中表现出很强的应用潜能。本论文的主要内容:采用改进后的Hummers法制备得到不同尺寸的纳米氧化石墨烯,随后在其表面共价修饰聚乙二醇和荧光分子Cy5.5,通过体外细胞实验得到最优化的纳米氧化石墨烯。然后在最优化纳米氧化石墨烯表面共价修饰靶向分子叶酸(FA),并且分别标记上核素125I以及荧光分子Cy5.5,形成核医学分子影像探针(125I-n GO-PEG-FA)及光学分子影像探针(n GO-PEG-Cy5.5-FA)。通过活体肿瘤模型的光学和核素显像,研究探针对肿瘤的靶向性和体内生物学性质,并用于肿瘤靶向性核素及光学分子影像的研究。全文共分为三章。第一章为绪论即综述。该章主要概括了石墨烯的制备、性质、结构和表面功能化的方法以及石墨烯的衍生物氧化石墨烯在生物体中的应用,同时介绍了纳米氧化石墨烯在核素成像和光学成像方面的应用,最后提出了本论文的研究设想。第二章为本论文核心内容即实验研究。首先,我们采用改进后的Hummers法制备得到不同尺寸的纳米氧化石墨烯,随后在其表面共价修饰聚乙二醇(PEG),通过体外细胞毒性实验、基于荧光分子Cy5.5标记的细胞激光共聚焦实验得到最优化的氧化石墨烯,进一步研究其细胞及活体中的应用。然后,通过在最优化纳米氧化石墨烯表面分别连接靶向分子叶酸(FA)、荧光染料分子Cy5.5和核素125I,得到叶酸靶向性功能纳米材料。体外实验表明,材料具有低的细胞毒性,激光共聚焦实验表明材料对高表达叶酸受体的4T1细胞具有显著的靶向作用,对A549没有明显靶向性。经尾静脉分别将靶向材料n GO-PEG-Cy5.5-FA和125I-n GO-PEG-FA注射进荷瘤鼠体内,对其分别进行活体小动物SPECT/CT和光学显像,发现材料n GO-PEG-Cy5.5-FA和125I-n GO-PEG-FA在4T1肿瘤内高度摄取,而封闭组的4T1肿瘤的摄取不明显,表明该纳米材料具有肿瘤叶酸受体靶向性。通过组织分布(HE染色)研究了该材料的小鼠体内毒性,结果表明,纳米材料没有表现出明显毒性,在活体小动物体内有较好的生物相容性。因此,该叶酸功能化纳米氧化石墨烯具有显著的叶酸受体靶向性,是叶酸受体阳性肿瘤的多模式分子影像探针的潜在的理想纳米载体,在癌症诊断和治疗一体化应用方面具有潜在的应用前景。第三章为总结与展望,主要是将本论文所得到的结果进行了归纳总结,并且展望了纳米氧化石墨烯在生物医学领域的应用前景。
[Abstract]:Nanocrystalline graphene oxide, the oxidation derivative of graphene, as a new two-dimensional carbon nano-material, has the properties of super large specific surface area and excellent photothermal effect, and has become a hot research topic in the field of nano-medicine. Nano graphene oxide contains a large number of active chemical groups, such as carboxyl, carbonyl, hydroxyl and epoxide groups, which are easy to be biochemically functionalized and have good biocompatibility. Therefore, in the field of biomedicine has shown a strong potential for application. The main contents of this thesis are as follows: Nano-graphene oxide with different sizes was prepared by modified Hummers method, and then covalently modified with polyethylene glycol and fluorescent molecule Cy5.5 on its surface. The optimized nano-graphene oxide was obtained by cell experiments in vitro. Then the target molecule folate was covalently modified on the surface of graphene oxide and labeled with radionuclide 125I and fluorescent molecule Cy5.5. the molecular imaging probe of nuclear medicine was formed by 125I-n GO-PEG-FAA and the optical molecular image probe (n GO-PEG-Cy5.5-FAA). Optical and radionuclide imaging of tumor models in vivo was used to study the tumor targeting and biological properties of the probe and to study the tumor targeting radionuclide and optical molecular imaging. The full text is divided into three chapters. The first chapter is the introduction. This chapter summarizes the preparation, properties, structure and surface functionalization of graphene and the application of graphene oxide, a derivative of graphene, in living organisms. At the same time, the applications of nano-graphene oxide in radionuclide imaging and optical imaging are introduced. The second chapter is the core content of this paper, that is, experimental research. Firstly, we prepared different sizes of graphene oxide by modified Hummers method, and then covalently modified PEGN on its surface. The optimized graphene oxide was obtained by laser confocal method based on fluorescent molecular Cy5.5 labeling, and its applications in cells and in vivo were further studied. Then, folic acid targeted functional nanomaterials were obtained by joining the target molecule folate, fluorescent dye molecule Cy5.5 and nuclide 125i on the optimized surface of graphene oxide. In vitro experiments showed that the materials had low cytotoxicity, and laser confocal microscopy showed that the materials had a significant targeting effect on 4T1 cells with high folate receptor expression, but not on A549 cells. The target materials, n GO-PEG-Cy5.5-FA and 125I-n GO-PEG-FA, were injected into the tumor bearing mice through the tail vein respectively. The SPECT/CT and optical imaging of small animals were performed respectively. It was found that the material n GO-PEG-Cy5.5-FA and 125I-n GO-PEG-FA were highly ingested in 4T1 tumor, but the 4T1 tumor uptake was not obvious in the blocking group. The results show that the nano-material has tumor folic acid receptor targeting. The toxicity of the material in mice was studied by tissue distribution HE staining. The results showed that the nano-material had no obvious toxicity and had good biocompatibility in vivo small animals. Therefore, the folic acid functionalized graphene oxide has significant folic acid receptor targeting and is a potential ideal nanometer carrier for multimode molecular imaging probes of folate receptor-positive tumors. It has a potential application prospect in the integrated application of cancer diagnosis and treatment. The third chapter is the summary and prospect, mainly summarizes the results obtained in this paper, and looks forward to the application prospect of nano-graphene oxide in biomedical field.
【学位授予单位】：上海师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ127.11;TB383.1

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