Preparation And Modification Of Gold Nanoparticles For Tumor Diagnosis And Therapy

Approximately 70% of cancer patients at some stage of the disease need radiation therapy, thereby increasing the effect of radiation therapy is very important. Radiation sensitizer is commonly used to improve the effectiveness of radiotherapy. However, conventional radiation sensitizer such as platinum, nitroimidazoles, paclitaxel and other drugs, have many disadvantages such as high toxicity, low selectivity for tumor cells, difficult to maintain an effective concentration in tumor area. So there is an urgent need to effectively target radiation sensitizer which have low toxicity and high selectivity, excellent radiosensitization effect. As a high atomic number material, Gold can enhance the radiate sensitization, improve biocompability effect. In addition, gold nanoparticles can be used in nuclear medical imaging, in order to realize real-time monitoring. However, it still remain unknown that how optimal size of the particles can be most effective in vivo, especially in the aspect of aggregating in target area, and having the best imaging and therapeutic effects.In current study, we built a platform with a tunable size gold nanoparticles. Modified gold nanoparticles based on this platform to study the early diagnosis and therapeutics for tumor, including: 1. Preparation of different size of gold nanoprobes and modification they with Gd(III),Tc-99 m and RGD for targeting tumor angiogenesis.2. Evaluation of the specialtiy of targeting gold nanoprobes in vitro and in vivo. 3.Evaluation of radiation enhancement effects of targeting gold nanoprobes.4. Preparation of Iodine-125 labeled gold nanoprobes for tumor theranostics.In conclude, we synthesis a tunable gold nanoparticles using one-step seed growth method, which has a good morphology, uniform particle size and mono-disperse property. Mainly in the following findings and conclusions:1. Successfully prepared a targeting probe of RGD@AuNP with the size of 30, 50 and 80 nm, respectively, which has a good biological behavior and tumor targeting ability, and specifically targeted to the αvβ3 receptor. It also can be used for radiosensitization,MR imaging and SPECT/CT imaging. We found that the nanoparticle with 30 nm size has the best effect both in imaging and therapeutic research, suggesting that it has great potential to become a novel type of probes in early diagnosis and therapeutics of cancer.2. Successfully prepared a targeting probe of 125I-RGD@AuNP with the size of 30 nm, which has good tumor targeting effect and leading to the maximum destruction of tumor cells. The treatment effect is most obvious, and can target to a small tumor. The novel theranosis probes is specific target for tumor and promising for clinical use in future.