| Due to excellent photo-physical properties of iridium complexes(large Stocks shifts, tunable UV-vis absorption spectra and fluorescence spectra by adjusting ligand, high quantum efficiency and long phosphorescence lifetime), iridium complexes acted as bio-imaging probes and cancer therapeutic agents have drawn more and more widely attention by researchers around the world. In this thesis, we have already designed and synthesized a serial of iridium complexes, and studied their application in bio-imaging and photodynamic therapy. This work was divided into two parts: 1. Synthesis and metal iridium complexes in solution photodynamic therapy applicationWe designed and synthesized three different ligands iridium complexes, and determined their structure by 1H NMR, 13 C NMR and MODI-TOF. We use some professional equipments to character the photophysical properties of iridium complexes, such as UV-vis, phosphorescent spectra and phosphorescent lifetime.As we all know, DMA as a standard reagent for detecting singlet oxygen. We used it to detect the production ability of singlet oxygen under > 400 nm visible light. The results tells us that N^N ligands have a great effect on the UV-vis absorption and emission properties of iridium complexes, especially in photodynamic effect property. 2. Synthesis of benzyl alcohol iridium complex nanoparticles and photodynamic effect under visible light irradiationWe found that iridium complexes have good photodynamic effect in solution. While it has some solubility in aqueous solution, but that still cannot meet the requirements of biological applications. In order to solve the poorly water-soluble iridium complex having this common different problem, we have designed and successfully developed a new method which it is different from the traditional use of complex cross-linking or doping to form nanoparticles. The new method uses alcoholic hydroxyl of benzyl alcohol iridium complexes with pyridine units N atoms to form hydrogen bonds between molecules, this way is called hydrogen bond self-assembly method. Hydrogen bond self-assembled polymer aggregates has the following characteristics. Firstly, hydrogen bond self-assembled nanoparticles have a defective repulsion subunits, thereby reducing the structural defects in the assembly process. Secondly, the hydrogen bond self-assembled nanoparticles is easy to prepare, and the synthesis process is simple and have a mild conditions, which can be repeated by varying the recipe proportional control morphology. Lastly, the hydrogen bond self-assembled nanoparticles has some other advantages, such as economic convenience, high efficiency and so on. Benzyl alcohol iridium complex has high alcoholic hydroxyl activity, using the hydroxyl group of benzyl alcohol iridium complex and pyridine ring N atom electron vacancy formation of a stable hydrogen bonds of polymer with diblock P4VP-b-PEO. The other end of a long chain polyethylene glycol(PEO) can be a good improvement in the water-soluble iridium complexes. The formation of micelles self-assembled through hydrogen bonding hydrophobic iridium complexes act as core, water-soluble hydrophilic PEO chain act as the shell of iridium complex nanoparticles at room temperature. The absorption and fluorescence spectra of benzyl alcohol iridium complex nanoparticles did not change significantly, which indicating that the iridium complex has been successfully assembled by hydrogen bonding to the polymer nanoparticles. We can use the outstanding optical properties of iridium complex features for cell labeling, cells imaging, and further application of photodynamic therapy at the solution level and cellular level induced by visible light. We studied cytotoxicity of nanoparticles in mouse fibroblast L929 cells and mouse 4T1 breast cancer tumor cells. Finally, we choose 4T1 mouse breast cancer cell to explore its photodynamic therapy tumor effect in the organism. We found that the iridium complex nanoparticles is a good-tumor photodynamic therapy agents. |
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