Research On Novel Metal Complexes As Biological Probes And Anticancer Drugs

Cells are the containers of various physiological and biochemical reactions,a variety of subcellular organelles are responsible for different types of physiological functions in living cells.The real-time monitoring of various subcellular structures is of vital importance for understanding the physiological state of cells,which is necessary for the diagnosis and treatment of cancer.Metal complexes are compounds formed by the chelation of transition metals and functional organic ligands via metal ligand bonds.Transition metal complexes have many excellent properties such as optical properties,light stability,high phosphorescence quantum yield,long phosphorescence lifetime,and extraordinary biocompatibility,which have been widely used as anticancer drugs and biological probes.Moreover,the emission wavelength,lifetime and quantum efficiency of this kind of phosphorescent complexes can be fine-tuned through the modification of ligand structures and metal centres.In this paper,three different Ir,and Os metal complexes have been designed and synthesized,their recognition for viscosity and nucleus DNA have been studied.Furthermore,the Mitochondrial targeted Iridium(III)complexes were promising for developing as PSs for photodynamic therapy.The Iridium(III)complexes(Ir1and Ir2)containing rotatable groups was designed and characterized by ¹H NMR and ESI-MS.The study of photophysics indicated that both Ir1and Ir2 features high sensitivity and selectivity for viscosity.Actually,The emission intensities and lifetimes of Ir1 and Ir2 are viscosity-dependent,Along with the increasing proportions of glycerol in the mixture solvent,the luminescence intensity of Ir1 was increased 35.7-fold at 555nm,and Ir2 was increased 1311.6-fold at 557nm.More importantly,Ir1 and Ir2 were living cell permeable and can be employed to track mitochondrial viscosity changes.Moreover,Ir1and Ir2 displayed potent cytotoxicity to A549 cells and Hep-G2 cells especially under the excitation of465 nm light but exhibit low cytotoxicity to normal cells.Further study indicated that both Ir1and Ir2 exhibit excellent effect of Photodynamic therapy,the generation of hydroxyl radicals and ¹O₂under light irradiation were detected by ESR and other commercial dyes,which indicated that Ir1 and Ir2 can work as effective photosensitizers for PDT.The Osmium(II)complexes azopyridine ligand was designed and characterized by ¹HNMR and ESI-MS.The luminescence properties of Osmium complex were studied by UV spectrua and fluorescence spectra,The results indicated that the Osmium complex was non-fluorescence.In this work,the intracellular spatial distribution of Os complex incubated with lung adenocarcinoma epithelial cells(A549)are investigated by Raman imaging,since Raman microscopy has made a big impact in many disciplines of science.The resulting observations shows that the Osmium complex is distributed throughout the cytoplasm region with a significant fraction entering into the nucleus.Futher studies shows that the azopyridine ligand of the osmium complex would selectively bind to DNA through an??stacking interaction.Besides,cytotoxic evaluation confirms that this Osmium complex could probely inhibit the growth of A549 cells compared with cisplatin.The advantageous properties make the developed Osmium complex promising for nuclear DNA targeting through Raman imaging and anticancer agent.