The Synthesis Of Fluorescent Molecular Probes Based On Coumarin And Oxanthene And Their Application In Cellular Imaging

Fluorescent probe technology has the advantages of easy operation,high sensitivity,low cost,convenience and speed in substance detection.Rhodamine dyes have been widely used in chemical analysis and life science fields due to their superior photophysical properties and are the most reported fluorophores.Coumarin has become a popular research target due to its excellent biocompatibility,strong fluorescence emission and good structural flexibility.In this paper,three fluorescent probes(Probe-R,RC and DC)have been designed and synthesized using Rhodamine and coumarin as the master bases.The main work of this thesis is as follows.The first part,(probe-R)was designed and synthesized based on Rhodamine B for the detection and recognition of copper ions by introducing 2,6-pyridinedicarbonyl chloride on its side chain.Probe-R showed high selectivity and sensitivity to Cu²⁺in a mixture of Et OH:HEPES(1m M,pH=7.40)=3:1(v/v).The detection limit was 0.149?M.The experimental results of probe-R on Hela cells indicate that probe-R has great potential for bioassay applications.In the second part,a novel Rhodamine dye was first synthesized that exhibits emission wavelengths of oxanthene and benzothiazole in the open and closed loop status of the five-membered spirochete,respectively.RC was finally synthesized by the introduction of acryloyl chloride.RC reacted to Cys in Et OH:HEPES(10m M,pH=7.40)=3:1(v/v)mixture,and the results of mass spectrometry titration showed that the probe showed selectivity for Cys by removing the umbrella heptameric ring,and the solution changed from colorless to fluorescent red.The detection limit of the probe RC is 7.923n M by the formula calculation,and the experimental results of RC on MCF-7 cells show that RC has great potential application in bioassay.In the third part,V-shaped bis-coumarin are synthesized by introducing a heterocyclic ring on the basis of coumarin.DC is synthesized by reacting it with benzyl chlorothiocarbonate.DC not only increases the?-conjugation system of coumarin,but also enhances the plane rigidity of the molecule.DC showed high selectivity and sensitivity to Hg²⁺in the DMSO:PBS(10m M,pH=7.40)=3:1(v/v)mixture solution,which showed yellow fluorescence.The mechanism of DC recognition was discussed using the experimental results of mass spectrometry titration.The detection limit of 52.94n M was calculated by the formula.Three novel fluorescent molecular probes were designed and synthesized in this thesis,and their physicochemical properties were investigated by a series of experiments including uv-vis,fluorescence spectroscopy,cytotoxicity and fluorescence imaging,etc.The results showed that the three molecular fluorescent probes have potential biological applications.