Multifunctionalnanoprobes Preparation And Their Application Studies In Theranostics Of Gastric Cancer

Nanomaterials have four nano-effects, and with unique properties such as sound, light, electricity, heat and magnetic properties. Development of nano theranostics for tumor based on advantages of nanometer materials has become a new research hotspot. The development of tumor molecular imaging technology is very fast, appearing some new techniques such as magnetic resonance imaging, fluorescence imaging, CT imaging, PET imaging.In recent years, photoacoustic imaging technology as an emergencing molecular imaging technology, develops very fast, which provides a new technical platform for the early diagnosis of tumor. However, how to develop multifunctional nanoprobes or contrast agents matched with these technologies, has become a challenging scientific problems.This doctoral dissertation tightly wraps around the key scientific problem of multifunctional nanoprobes for gastric cancer theranostics, designed and prepared multifunctional nanoprobes for molecular imaging of gastric cancer, designed and prepared multifunctional nanoprobes for gastric cancer targeted imaging and simultaneous therapy, and those prepared multifunctional nanoprobes also were applied to investigate the feasibility of using those nanoprobes for in vitro gastric cancer cell imaging and in vivo gastric cancer targeted imaging and therapy. The main research contents and results are as follows:1. Dendrimer modified single wall carbon nanotubes were prepared and characterized, survivin siRNA expression vector was designed and constructed and identified, results showed that the dendrimer modified carbon nanotubes could efficiently deliver Survivin siRNA into gastric cancer MGC803cells, and the survivin siRNA could be released from the complexes, played the role of inhibition of gastric cancer cell growth, inhibited the growth of in vivo gastric carcinoma cells; dendrimer modified single wall carbon nanotubes showed low cytotoxicity, in the concentration range of0.5mg/ml, exhibited good biocompatibility. G4.0PAMMAM dendrimer modified the single wall carbon nanotubes is a safe, efficient siRNA delivery system, and owns great potential in applications such as fluorescence imaging and synchronization of siRNA treatment of gastric cancer. 2. The nanoprobes of RGD-conjugated multiwalled carbon nanotubes coupled with gold nanorods were prepared and characterized, could be targeted in vitro and in vivo gastric cancer cells, and can be internalized by gastric cancer cells, clearly showing the gastric cancer vascular, realized the targeted photoacoustic imaging of gastric cancer. This RGD-conjugated multiwalled carbon nanotubes coupled with gold nanorods own great potential in applications such as gastric cancer targeted photoacoustic imaging.3. By using immunohistochemical staining method, expression of a subunit of ATP synthase in172specimens of gastric cancer tissues was investigated, and the correlation between expression levels of a subunit of ATP synthase and classification of gastric cancer also was analyzed. ATP synthase α subunit monoclonal antibody, HAI-178antibody conjugated fluorescent magnetic nanoparticles were prepared, and used for targeted the fluorescence and NMR dual modality imaging of gastric cancer cells in vitro and in vivo and magnetic heat treatment, exhibit great potential in applications such as clinical diagnosis and therapy of gastric cancer in near future.4. Use HBsAg detection as a example, the principle and method of gold nanoparticles quenching quantum dots fluorescence signal for the ultra sensitive detection of hepatitis B surface antigen was established, the detection limit was0.928ng/ml, lay the foundation for the clinical application in the detection of multiple tumor markers in near future.