基于纳米金红外热疗方法对HepG2肝癌的原位治疗

Gold nanoparticles(GNPs) have photosensitive properties to infrared light, a wavelength region that provides maximal penetrate of tight tissue. When excited by the near infrared light (NIR), gold nanoparticles can convert light energy into heat energy and heat up the surrounding environment. This property allow them selectively destruct target tissue, provide a novel method to mediate photothemal ablation of cancer cells. Local hyperthermia does not injury the surrounding healthy tissue. GNPs have a high affinity. Antibodies and other targeting moieties can be conjugated to the gold surface. On one hand it can further enhance biocompatibility of GNPs,on the other hand it can integrate composite material with cancer result in tumor targeting. At present, there are inherent problems and potential problems to determine precise location of deep tumor in the body. Optimism towards the ulitiazation of GNPs to tumor targeting are kept in cancer close to skin such as breast cancer or melanoma of skin. It has not been reported for treatment on deep solid tumor. In this project, we will break through the traditional model preparation method for transplantation tumor and establish orthotopic hepatocellular carcinoma model. Infrared photothemal therapy was implemented in situ cancer. For the deep tumors can not be directly observed, we will prepare composite material with core-shell structure. This composite material is composed of a rare-earth nanocrystalline core covered a thin gold shell. Since the core has upconversion fluorescence function and the gold shell has photothermal property, the composite nanomaterial can make image in the organism body. We may get image to monitor the tumor position in order to direct irradiation site for photothermal therapy. We will also conjugate the composite material with Arginine-glycine-aspartic acid ( RGD ) to make it target to tumor. The aim of this poject is to explorate the dose of composite material and laser irradation dose indepth, and observe the tumor inhibiting effect. We will make in situ treatment condition optimized. We will also have safety assessment on biological safety and provide theoretical and experimental evidence before the application of composite material in cancer therapy become a clinical reality.

纳米金具有红外光敏特性，经近红外激光辐照后，可以使局域温度升高，破坏靶组织，实现肿瘤热疗。它同时还具有高度亲和性，能够通过表面修饰结合生物大分子，实现与肿瘤的靶向连接。目前由于深部肿瘤定位等问题难于解决，国际上纳米金靶向热疗技术多用于乳腺癌及皮肤癌等浅表肿瘤的治疗，对于深部实体瘤的治疗作用尚未见报道。本项目拟突破传统移植性肿瘤模型的制备方法，建立原位HepG2肝癌模型，进行原位红外光热治疗。由于深部肿瘤在体表无法被直接观察到，本项目拟采用兼具肿瘤红外热疗和上转换荧光标识的稀土上转换纳米晶@金壳双功能复合材料，先在在生物体内进行荧光成像，监测肿瘤部位，指导辐照区域，再进行光热治疗。肿瘤的靶向性拟通过在金壳外面连接RGD来实现。本项目将深入探索复合纳米材料的剂量、激光辐照剂量对肿瘤的影响，获得优化的原位治疗条件，并对生物安全性进行评估，为纳米金红外热疗应用于临床提供理论和实验依据。

本项目深入研究了金纳米复合材料在肿瘤细胞治疗方面的应用，同时对复合纳米材料在生物检测应用方面进行探索。在项目进行期间，我们制备了具有近红外光敏特性的纳米金棒，具有有负载药物功能的纳米复合材料Au@mSiO2，以及具红外辐照肿瘤热疗和上转换荧光标识功能的NaYF4@ Au核壳双功能复合纳米材料。体外试验中，我们利用金纳米复合材料实现了对肿瘤细胞的高效灭活，初步研究了其作用机制，并在共聚焦显微镜下，实现对细胞的监控。体内实验中，我们利用复合金纳米材料，对原位肝癌小鼠进行治疗，从形态学、蛋白表达及mRNA表达等方面检测了细胞凋亡，对其灭活机制进行初步探索。研究中发现，复合纳米材料可增加促凋亡相关基因的表达，降低凋亡抑制基因的表达，其对肿瘤细胞的杀伤作用可通过促凋亡来实现。金纳米棒及纳米复合材料具有高的生物相容性及低毒性，生物应用安全，是治疗肿瘤的“绿色疗法”。