Study On The Synthesis, Characterization, Metal Ions Recognization And Antibacterial Activity Of Boron Dipyrromethene (Bodipy) Derivatives And Nanocomposites

More and more diseases have been caused by bacterial infections.Traditional treatment with antibiotics is likely to cause bacterial resistance while antibacterial photodynamic inactivation?aPDI?has the advantages of non-invasiveness,less harmfulness and no drug resistance,which has become the main treatment method in the fields of biomedicine,environmental science and materials chemistry.Photosensitizer,oxygen and light constitute the three elements of photodynamic therapy and the photoresponsive photosensitizer has important application prospects in the field of environment and biomedicine.BODIPY dyes become a research hotspot because of its high fluorescence quantum efficiency,large molar extinction coefficient,good photostability and easy modification.Lipase is highly expressed in tumors and bacteria,and lipase-recognized dyes have bacterial selectivity.Photosensitizers for bacteria recognition can be obtained by introducing lipase-recognized functional groups to modify the structure of BODIPY core.Nano BODIPY dyes with excellent properties can be obtained by studying on the supermolecular self-assembly of photosensitizers,which is expected to be applied on antibacterial photodynamic inactivation and probe for ion detection.The thesis gives introductions on antibacterial photodynamic inactivation,biomolecule and heavy metal ion detection of BODIPY derivatives and the research progress of photoacid generators.Eight new BODIPY derivatives and one nanocomposite were designed,synthesized and their structures have been characterized by nuclear magnetic resonance?NMR?,mass spectrometry?MS?,ultraviolet and visible spectrophotometry?UV-vis?,fluorescence spectrophotometry,scanning electron microscope?SEM?and other methods.The antibacterial effects and metal ions recognition of BODIPY derivatives were explored in depth.The main innovation results are as follows:?1?Five new fluorescent dyes?BDP-1^BDP-5?were synthesized by coupling functional antibacterial groups with BODIPY and lipase affinity tests and antibacterial assays were conducted.The adamantane-conjugated BODIPY?BDP-2?showed the highest lipase affinity and found to be active against Escherichia coli?E.coli?.The water-soluble nanoparticles BDP2-Br₂@mPEG was synthesized by the bromination of BDP-2 and nano self-assembly with DSPE-mPEG.The nanoparticles show low toxicity on mammalian cells and can rapidly inactivate E.coli under visible light.Experimental results demonstrate that BDP2-Br₂@mPEG produce reactive oxygen species under illumination and destroy the cell membrane of bacteria and can be a new type of photo-activated sustainable antibacterial material.?2?The synthetic route of BDP-1 was optimized and the yield of BDP-1 was greatly improved.The fluorescence spectrum showed that BDP-1 had maximum emission at 508 nm and a specific response to Cu²⁺.The combination between BDP-1and Cu²⁺was studied.Mass spectrometry showed that BDP-1 formed[CuCl₂-?BDP-1?₂]·OH^-complex with Cu²⁺and the emission of BDP-1 was quenched.In addition,BDP-1 can be used to detect the content of Cu²⁺in the serum of mice with a linear detection range of 0.45?M-27.71?M.The results show that BDP-1 is likely to be a fluorescent probe for detecting the content of Cu²⁺in biological serum.?3?Two BODIPY derivatives of p-nitrobenzenesulfonate?BDP-S and BDP-S2?were synthesized and the emission changes,acid generation and inhibition effects on E.coli induced by light were studied in depth.BDP-S was found to produce acid species under LED illumination and lower the pH of the solution,which make it a kind of hydrophobic proton donor.Light-induced antibacterial results indicate that BDP-S has a high inhibitory effect on the growth of E.coli.In addition,there is solvent effect between BDP-S and polar solvents,in which BDP-S shows fluorescence“turn-on”in ethyl acetate?EA?and tetrahydrofuran?THF?.Our research results demonstrate that BDP-S is a very promising photoacid sterilant and can also be applied for the qualitative and discrimination for common polar solvents.