Study On The Photodynamic Activity Of A Platinum Phenylenediimine Complex Modified With Coumarin

Cancer has seriously threatened to human life and health.In recent years,photodynamic therapy?PDT?has become an attractive treatment due to its less toxic and side effects and good selectivity to tumor cells.It achieves the diagnosis and treatment of a variety of tumors through the photosensitizer,light and oxygen molecules.At present,photodynamic therapy is still facing many problems,which affect its clinical application.For example,the solubility of the photosensitizer in water is poor,which leads to its low bioavailability.The photodynamic activity of the photosensitizer is low due to its weak ability to produce singlet oxygen.The recognition ability of the photosensitizer towards the cancer tissue is also weak.In addition,the absorption wavelength of the photosensitizer is relatively short as well.How to improve the photodynamic activity of the photosensitizer is still the key problem to improve the therapeutic effect of photodynamic therapy.Platinum phenylenediimine complexes have strong absorption band in the red light region and they are photodynamic therapeutic agents with great potential.In this paper,a new coumarin-modified o-phenylenediamine ligand was firstly synthesized,and a new platinum phenylenediimine photosensitizer was synthesized using this ligand.The singlet oxygen production capability of the photosensitizer was studied by fluorescence spectroscopy.In addition,the in vitro photodynamic activity of the photosensitizer against human colon cancer cells and human non-small cell lung cancer cells were studied by MTT assay.The influence of magnetic composite nanoparticles on the photodynamic activity of the new photodynamic therapeutic agent was also studied.The specific work is as follows:?1?Using 7-amino-4-methylcoumarin and 4-amino-3-nitrobenzoic acid as reactants,a new o-phenylenediamine ligand modified with coumarin was prepared through an amidation reaction and a nitro reduction reaction,thereafter a new coumarin-modified platinum phenylenediimine photosensitizer was synthesized with this ligand.The structures and components of the corresponding ligands and complexes were analyzed by UV Vis,IR,NMR,fluorescence and elemental analysis.The results showed that the novel platinum phenylenediimine photosensitizer modified with coumarin was synthesized.?2?1,3-diphenylisobenzofuran?DPBF?was used as capture agent.The ability of the complex to produce singlet oxygen was evaluated by fluorescence spectroscopy.The results show that the complexes have good ability to produce singlet oxygen.?3?Two different magnetic nanocomposites,Fe₃O₄@Si O₂-APTES and Fe₃O₄@Si O₂-APTES-TPP,were used as carriers of the coumarin-modified platinum phenylenediiimine photosensitizer,affoding the two drug-loaded nanocomposites.The drug-loading rate of the two drug-loaded nanocomposites was measured to be 7.9%and 10.2%,respectively.?4?The in vitro photodynamic activity of the coumarin-modified platinum phenylenediimine photosensitizer and the two drug-loading nanoparticles against human colon cancer HCT116 cells and human non-small cell lung cancer A549 cells were studied by MTT assay.The results showed that the coumarin-modified platinum phenylenediimine photosensitizer was highly phototoxic to the two tumor cells studied.When magnetic nanocomposites were used as the carriers of the photosensitizer,the photodynamic activity of the drug could be significantly enhanced.