肿瘤乏氧响应的光学探针研究

发布时间：2018-10-15 06:57

【摘要】：绝大多数实体肿瘤都具有特异性的乏氧微环境,肿瘤的乏氧程度是预后的重要标志之一,此外,乏氧还与肿瘤对化疗和放疗的耐药直接相关。因此,对肿瘤乏氧的成像与测量对于癌症的诊断和治疗极为重要。目前,可用于肿瘤乏氧的成像技术中,正电子断层扫描成像和磁共振成像存在着设备昂贵,背景噪音高,难以实时连续观测等缺点。而光学成像技术具有成本低廉,便携性好,操作简单,便于实时观测等独特的优势,但满足应用需求的光学探针严重不足,光学成像技术用于肿瘤乏氧成像还需进一步研究和发展。为了探索肿瘤乏氧微环境的光学成像,我们需要发展出满足活体应用需求的高灵敏度高特异性的乏氧光学探针。目前已报道的乏氧光学探针主要包括磷光发射的金属配合物和含有乏氧敏感基团的有机小分子荧光探针,相关的研究主要还集中在体外性质的表征,活体层面的肿瘤乏氧成像尝试还鲜有报导。本论文中,作者基于铱配合物和生物相容性高分子材料,开发出新的大分子光学探针,所开发的探针具有近红外发射和高度氧敏感性,还具有良好的水溶性和生物相容性,在体内具有长循环的性质,还能体现出肿瘤的高通透和滞留(EPR)效应。利用所开发的大分子探针,作者开展在细胞和活体二个层面上对肿瘤乏氧微环境的光学成像和测量进行了研究。具体的研究内容如下：1)合成一种铱配合物-聚乙烯吡咯烷酮大分子乏氧光学探针,测试所合成的大分子探针的基本光学性质,并在细胞单层细胞和三维多细胞球体中,对大分子探针的乏氧响应能力进行测试。此外,将探针在体内小鼠皮下肿瘤模型,皮下癌细胞模型,以及小鼠淋巴转移模型中进行乏氧成像的测试。另外,对探针分子在体外和体内条件下的生物相容性和毒性进行表征。2)以铱配合物-聚乙烯吡咯烷酮大分子和聚己内酯-b-聚乙烯吡咯烷酮为基础,合成含铱配合物的纳米胶束探针。测试纳米胶束的基本结构和光学性质,在单层细胞和三维多细胞球体中对其乏氧敏感性质进行测试。在体内应用中,将所合成的纳米胶束探针应用于小鼠血管肺转移模型和脚掌淋巴结转移模型的乏氧成像。3)提出了一种两步放大肿瘤微环境信号的探针设计思路,以铱配合物和聚乙二醇为基础,合成一种对酸化和乏氧连续响应的大分子探针。测试探针的基本光学性质,以及对pH值和氧分压的敏感性。在细胞中测试探针在不同pH值条件和不同氧分压环境下的细胞摄取性质和信号响应情况。此外,在小鼠皮下肿瘤模型和皮下癌细胞模型中,对探针的连续响应特征进行测试。另外,测试探针的生物相容性和毒性情况。
[Abstract]:Most solid tumors have specific hypoxic microenvironment. The degree of tumor hypoxia is one of the important prognostic markers. In addition, hypoxia is directly related to tumor resistance to chemotherapy and radiotherapy. Therefore, the imaging and measurement of tumor hypoxia is very important for the diagnosis and treatment of cancer. At present, positron tomography (PET) and magnetic resonance imaging (MRI) have the disadvantages of expensive equipment, high background noise and difficult real-time continuous observation among tumor hypoxic imaging techniques. However, the optical imaging technology has the advantages of low cost, good portability, simple operation and convenient real-time observation. The application of optical imaging technology in tumor hypoxic imaging needs further research and development. In order to explore the optical imaging of tumor hypoxic microenvironment, we need to develop a highly sensitive and specific hypoxic optical probe to meet the needs of in vivo applications. At present, the reported hypoxic optical probes mainly include phosphorescent metal complexes and organic small molecule fluorescent probes containing hypoxia sensitive groups. The related studies mainly focus on the characterization of the properties in vitro. In vivo tumor hypoxic imaging attempts are rarely reported. In this paper, a new macromolecular optical probe was developed based on iridium complexes and biocompatible polymer materials. The developed probe has near infrared emission, high oxygen sensitivity, good water solubility and biocompatibility. It has the property of long circulation in vivo and can reflect the high permeability and stranded (EPR) effect of tumor. The optical imaging and measurement of tumor hypoxic microenvironment at both cellular and in vivo levels were studied using the developed macromolecular probes. The specific research contents are as follows: 1) Synthesis of an iridium complex-polyvinylpyrrolidone macromolecule hypoxia optical probe, test the basic optical properties of the synthesized macromolecular probe, and in cell monolayer cells and three-dimensional multicellular spheres, The hypoxia response ability of macromolecular probe was tested. In addition, hypoxia imaging was performed in mice subcutaneous tumor model, subcutaneous cancer cell model and lymphatic metastasis model in vivo. In addition, the biocompatibility and toxicity of probe molecules in vitro and in vivo were characterized. 2) based on the iridium complex polyvinylpyrrolidone macromolecule and polycaprolactone bpolyvinylpyrrolidone. Synthesis of nano-micelle probes containing iridium complexes. The basic structure and optical properties of nano-micelles were tested, and the anoxia-sensitive properties were tested in monolayer cells and three-dimensional multicellular spheres. In vivo application, the synthesized nano-micelle probe was applied to hypoxic imaging of mouse vasopulmonary metastasis model and plantar lymph node metastasis model. 3) A two-step probe design idea for amplifying tumor microenvironment signal was proposed. Based on the iridium complexes and polyethylene glycol, a macromolecular probe was synthesized for continuous response to acidification and hypoxia. The basic optical properties of the probe and its sensitivity to pH and oxygen partial pressure were tested. The cellular uptake properties and signal responses of the probes under different pH values and oxygen partial pressures were measured in cells. In addition, the continuous response of the probe was tested in mouse subcutaneous tumor model and subcutaneous cancer cell model. In addition, the biocompatibility and toxicity of the probe were tested.
【学位授予单位】：南京大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：R73-3

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