基于介孔有机氧化硅的肿瘤多模式成像及其引导下的增效治疗

发布时间：2018-10-23 16:39

【摘要】：传统的肿瘤治疗方法存在局限性,比如化疗毒副作用较强,而肿瘤中的乏氧环境又抑制了放疗效果。纳米材料应用于生物医学为肿瘤的诊断与治疗提供了新的方法,它可以把多种成像方式选择性地与治疗模式结合起来。"诊疗一体化"——将成像与治疗能力结合于同一纳米材料,已广泛应用于药物递送示踪、治疗效果监测以及成像引导下的治疗。介孔有机氧化硅纳米颗粒分散性好、尺寸均一、比表面积大、可生物降解且生物相容性高,是肿瘤诊疗体系的理想载体。本论文围绕构建基于介孔有机氧化硅的肿瘤诊疗一体化探针及其应用展开了系统性研究,主要包括以下三方面工作:一、介孔有机氧化硅诊疗一体化系统用于肿瘤靶向成像与增效化疗构建基于含硫醚键的周期性蛋黄-蛋壳结构介孔有机氧化硅(PMOs),表面稳定连接近红外荧光分子Cy5.5与靶向人表皮生长因子受体-2(Her2)的亲合体(affibody),使之具备近红外荧光成像及靶向Her2阳性肿瘤细胞的能力。利用纳米粒子骨架内硫醚键的结构,空腔内装载的化疗药物阿霉素(DOX)可在肿瘤细胞内谷胱甘肽(GSH)的作用下响应性释放。在10mM的GSH溶液中24h内药物释放量可达84.8%,是无GSH刺激条件下释放量的两倍多。此外,药物还可在pH的刺激下响应性释放,中性环境(pH 7.4)中24 h内药物释放量为31.7%,而酸性环境下(pH 5.0)24 h释放量可达53.6%。激光共聚焦扫描显微镜以及细胞流式分析证明该诊疗系统可高效靶向Her2阳性肿瘤细胞并被其摄取,从而有效杀伤肿瘤细胞。同时,Cy5.5具有良好的近红外荧光成像能力,可用来监测细胞内药物的分布、递送以及释放。同时,细胞实验以及动物器官组织病理切片表明该诊疗一体化系统具有良好的生物相容性,为后续生物应用打下良好基础。总之,该研究开发了具有靶向肿瘤细胞、近红外荧光成像以及GSH/pH双响应药物释放能力的新型肿瘤细胞靶向成像与增效化疗系统。二、三响应可降解介孔有机氧化硅硫化铜诊疗一体化系统用于温热增强肿瘤化疗热疗与化疗有协同治疗作用,二者的联合治疗可大幅度提高肿瘤治疗效果。该研究提出温热效应可增强化疗疗效的新观念,并在体外细胞与在体肿瘤模型中探讨验证了协同治疗机制。通过原位生长硫化铜的方法构建了一种新型的基于硫化铜、周期性蛋黄-蛋壳结构介孔有机氧化硅(CuS@PMOs)可生物降解诊疗一体化系统,用于光热转化以及药物递送。制备的CuS@PMOs具有很强的化疗药物DOX装载能力,高达470 mg/g。DOX的释放可由三重刺激精确控制,包括肿瘤细胞内高浓度的GSH、肿瘤内酸性环境以及外部激光照射。实验结果表明,激光照射CuS产生的温热极大提高了体外肿瘤细胞和在体肿瘤对纳米颗粒的摄取,从而显著增强化疗疗效,完全抑制了肿瘤的生长。同时,DOX本身的荧光成像能力可用于监测药物的递送与释放。三、温热响应性的全氟戊烷气化用于针对乏氧肿瘤的增效放疗肿瘤的乏氧环境造成对放疗的耐受,因此,寻找可高效输送氧气至肿瘤区域的方法是解决问题的关键。全氟戊烷(PFP)对氧气有强亲和力,在体内的沸点为40-50℃,构建基于硫化铜、中空介孔有机氧化硅纳米颗粒(HMON@CuS)的递送系统,将携带氧气的PFP(O2-PFP@HMON@CuS-PEG)输送至肿瘤区域,用于乏氧肿瘤的增效放疗。激光照射后CuS产生的温热可使PFP发生液气相变,产生的气泡不仅可以增强超声成像信号,还可以促进氧气快速释放,推动氧气在乏氧肿瘤内扩散,细胞实验证明该方法可大幅度增强乏氧肿瘤细胞的放疗疗效。硅球表面螯合核素64Cu后,可利用正电子发射断层扫描(PET)成像观察纳米颗粒在小鼠体内的分布,实验结果表明纳米颗粒有较长的血液半衰期,尾静脉注射24 h后在肿瘤区域聚集达到高峰,并可持续至48 h。另外CuS还具有光声(PA)成像能力。因此,在近红外激光的刺激下,该诊疗一体化系统可实现PET/超声/光声三模态精确影像引导下的针对乏氧肿瘤的增效放疗,具有很好的临床应用前景。
[Abstract]:Traditional methods of tumor therapy have limitations, such as the strong toxic and side effects of chemotherapy, and the spent oxygen environment in tumors also inhibits the effect of radiotherapy. The application of nano-materials in biomedicine provides a new method for diagnosis and treatment of tumor, which can combine multiple imaging methods with the treatment mode. "Integration of diagnosis and treatment" The combination of imaging and therapeutic capabilities with the same nanomaterials has been widely used in drug delivery tracing, treatment effectiveness monitoring, and imaging guided therapy. The mesoporous organic silicon oxide nano-particles have good dispersibility, uniform size, large specific surface area, biodegradability and high biocompatibility, and is an ideal carrier of the tumor diagnosis and treatment system. In this paper, a systematic study on the diagnosis and treatment of tumor diagnosis and treatment based on mesoporous organic silicon oxide is carried out, which mainly includes the following three aspects: 1. the mesoporous organic silicon oxide diagnosis and treatment integration system is used for constructing a periodic egg yolk-eggshell structure mesoporous organic silicon oxide (PMOP) based on a thioether bond for tumor target imaging and synergistic chemotherapy, The surface stably connects the near-infrared fluorescent molecule Cy5. 5 with the affinity body of the target human epidermal growth factor receptor-2 (Her2) so as to have the capability of near-infrared fluorescence imaging and targeting Her2 positive tumor cells. With the structure of the sulfide bond in the nano particle framework, the chemotherapy drug adriamycin (DOX) loaded in the cavity can be released in response to the action of glutathione (GSH) in the tumor cells. The amount of drug released within 24h of 10mM GSH solution can reach 84.8%, which is more than double the release amount under the condition of GSH-free stimulation. In addition, the release of drug in 24 h in neutral environment (pH 7.4) was 31.7% in neutral environment (pH 7.4), while the release amount of pH 5.0 was 53.6% in acidic environment (pH 5.0). Laser confocal scanning microscope and cell-flow analysis show that the diagnosis and treatment system can target Her2-positive tumor cells efficiently and can be taken up, thereby effectively killing tumor cells. At the same time, Cy5.5 has good near infrared fluorescence imaging capabilities to monitor the distribution, delivery, and release of intracellular drugs. At the same time, the cell experiment and pathological section of animal organ tissue show that the diagnosis and treatment integration system has good biocompatibility and lays a good foundation for the subsequent biological application. In summary, this study has developed a novel tumor cell targeting imaging and synergistic chemotherapy system with targeted tumor cells, near infrared fluorescence imaging, and GSH/ pH dual response drug release capabilities. secondly, the three-response degradable mesoporous organic silicon oxide thermal treatment integrated system is used for the combination therapy of hyperthermia and chemotherapy and chemotherapy, and the combination therapy can greatly improve the treatment effect of the tumor. This study suggested that the warming effect could enhance the efficacy of chemotherapy, and discussed the mechanism of synergistic treatment in vitro and in vivo tumor model. The invention discloses a novel biodegradable diagnosis and treatment integrated system based on a human body, a periodic egg yolk-eggshell structure and a mesoporous organic silicon oxide (CuS @ PMOs), which is used for photothermal conversion and drug delivery. The prepared CuS @ PMOP has strong chemotherapeutics DOX loading capacity, and the release of DOX is up to 470 mg/ g. The release of DOX can be controlled accurately by triple stimulation, including high concentration of GSH in tumor cells, acidic environment in tumor and external laser irradiation. The experimental results show that the hyperthermia produced by laser irradiation greatly improves the tumor cells in vitro and the uptake of nano-particles in body tumors, thus remarkably enhancing the curative effect of chemotherapy, and completely inhibiting the growth of the tumor. Meanwhile, the fluorescence imaging capability of DOX itself can be used to monitor drug delivery and release. Three, thermoresponsive perfluoropentane gasification is a key to solving the problem by finding a way to efficiently deliver oxygen to a tumor region due to a spent oxygen environment of a synergistic radiotherapy tumor for a spent oxygen tumor. Perfluoropentane (PFP) has a strong affinity for oxygen, the boiling point in the body is 40-50 DEG C, and a delivery system based on hydrogen cyanide, hollow mesoporous organic silicon oxide nanoparticles (HMON @ CuS) is constructed, and PFP (O2-PFP @ HMON @ CuS-PEG) carrying oxygen is delivered to the tumor area for synergistic radiotherapy of the spent oxygen tumor. The heat generated by the CuS after laser irradiation can cause the PFP to generate liquid-gas phase change, the generated bubbles can not only enhance the ultrasonic imaging signal, but also promote the rapid release of oxygen, promote the diffusion of oxygen in the spent oxygen tumor, The cell experiment proves that the method can greatly enhance the radiotherapy curative effect of the spent oxygen tumor cells. The distribution of nano-particles in mice can be observed by positron emission tomography (PET) imaging. The experimental results show that the nanoparticles have a long half-life of blood, and after 24 hours after intravenous injection, the peak is reached in the tumor area. and may continue to 48 h. Alternatively, the CuS also has an optical acoustic (PA) imaging capability. Therefore, under the stimulation of the near infrared laser, the integrated system of the diagnosis and treatment can realize the synergistic radiotherapy aiming at the spent oxygen tumor under the precise image guidance of the PET/ ultrasonic/ optical sound three modes, and has good clinical application prospect.
【学位授予单位】：南京大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：R730.5

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