Preparation Of Nano-gold With Special Morphology And Its Application In Tumor Near-infrared Photothermal Therapy

With the aggravation of worldwide food and environment problem, cancer has become the main cause of global morbidity and mortality. The key to cancer treatment is early detection and early treatment. In the high incidence of cancer, finding a highly efficient therapeutic approach has been widely studied. At present, the common cancer treatments are surgical treatment, drug therapy and radioactive therapy. But these traditional methods of treatment have some shortcomings. Photothermal therapy is a kind of cancer treatment, that use photothermal agents to transform the photon energy into heat energy. And the heat can kill tumor cells. In recent years, photothermal therapy has been widely studied. This thesis establish high efficient photothermal agent, that was applied to the photothermal therapy of the cancer cell and cancer. Meanwhile we have studied the mechanism of the death of cancer cell. The main results are as follows:We synthesized Au-attapulgite nanocomposites, that has high absorption ability in NIR region, and we used it to treat A549 cells. The synthesis of the tubelike Au nanostructures was achieved by assembly of Au NSs ??15 nm in diameter? through electrostatic interactions on the surface of attapulgite,which was used as a template. The formation of the Au-attapulgite nanocomposites can be further verified by transmission electron microscopic ?TEM? images, X-ray diffraction ?XRD?, energy-dispersive X-ray?EDX? spectrum and the UV-vis absorption characteristics. All feature demonstrating the synthesis of the Au-attapulgite nanocomposites, and also suggests that the assembly of the Au NSs on the attapulgite surface is not simply aggregation to form large Au nanoparticles but is an assembly along the attapulgite surface to form a tubelike nanocomposite. The nanocomposites exhibit similar localized surface plasmon resonance absorption characteristics to those of Au nanorods with a longitudinal absorption mode that shifts to the NIR region ?about 670 nm?. Moreover,the nanocomposites have a high photothermal conversion efficiency of 25.6%. The cytotoxicity of the Au-attapulgite nanocomposites was first estimated by an MTT assay. The results indicated that the nanocomposites have good biocompatibility. Their photothermal therapy effect is studied using A549 cells as examples. The A549 cells almost died after they were incubated with the nanocomposites(at 100?g mL^-1) for 12 h and irradiated by an 808 nm laser with a power density of 0.5 W cm-2 for 15 min. And the tumors of nude mice can also be effectively ablated without regrowth during the period of observation ?at least 10 d? after photothermal therapy.We synthesized branched gold nanoparticles for photothermal therapy of human breast cancer cells ?MCF-7?. We synthesized branched gold nanoparticles by one-pot chemical reduction method. From the TEM images of branched gold nanoparticles, the dimensions of the branched gold nanoparticles can be estimated to be 100 nm, and it is high branched. The UV-vis spectrum of branched gold nanoparticles shows a typical peak at 700 nm. The nanocomposites have a high photothermal conversion efficiency of 23.1%.The cytotoxicity of the branched gold nanoparticles was estimated by MTT assay, the results indicated that the nanocomposites have good biocompatibility. And it has surface enhanced Raman scattering ?SERS?. The surface enhanced Raman spectroscopy of MCF-7 cells and the MCF-7 cells after treat have been studied. Their photothermal therapy effect is studied using MCF-7 cells and MCF-7 cell bearing nude mice as examples. The MCF-7 cells almost died after treatment. And the tumors of nude mice can also be effectively ablated without regrowth during the period of observation after photothermal therapy.