Design And Application Of Bio-reactive Sulfur Species Small Molecule Fluorescent Probe

Bio-reactive sulfur species small molecule,including cysteine(Cys),homocysteine(Hcy)and glutathione(GSH),hydrogen sulfide(H2S)and sulfur dioxide(SO2)and so on,play irreplaceable roles in regulating specific processes of life phenomena occurring in living organisms and maintaining the balance of life system.Nevertheless,the abnormal concentrations of them in organism are related to many diseases.Based on the idea of identifying bio-reactive sulfur small molecules,specific response sites were used to construct fluorescent probes for the specific and reversible detection of Cys in the water environment,the specific detection of SO2 and the discrimination between thiols and H2S/SO2,and successfully applied them in imaging experiments.Specific researchworks are as follows:1.The physiological roles and related application of bio-reactive sulfur species small molecule and the design ideas of of fluorescent probes in this paper were introduced.2.We utilized unsaturated olefinic bond as thiol binding site and carboxyl group as terminal anchor to fix the amino group of Cys to design probe 2-1 that featuring reversible and specificity towards Cys through nucleophilic addition reaction.The probe is almost non-fluorescent.With the addition of Cys,the unsaturated olefin bond undergoes nucleophilic addition reaction with Cys to form photoinduced electron transfer(PET),and the fluorescence intensity of the system at 500 nm was enhanced by 78 times.What's more,in an aqueous environment,the addition of NEM or H2O2 allows the fluorescence of the 2-1-Cys system to achieve a cyclic response.Exogenous Cys was successfully detected in A549 and Hela cells.The probe can be further applied to fluorescent labeling and imaging of Cys in an organism.3.In the structure of 3-1,when the good biocompatibility coumarin was used as fluorophore,cyano group and carboxyl group as double-absorbing electron were introduced to link the double bond to enhance the interaction between the probe 3-1 and sulfite.Therefore,D-?-A form constructs intramolecular charge transfer(ICT),the probe had a weak yellow fluorescence emission(565 nm),after addition reaction taking place between the probe and bisulfate,conjugated double bond was broken,the system showed a short-wavelength fluorescence emission(483 nm),which achieves the ratio of probe to sulfite fluorescence detection.The study found that dual electron-withdrawing groups enhanced the specificity and sensibility(a low detection limit with 82 nM)of the probe recongnizing bisulfate.These excellent properties led directly to the use of probes to image sulfur dioxide in living cells.Further applications are still being on the way.3.A bio-reactive sulfur species small molecule compound for thiols and its metabolites in cells,based on coumarin as a fluorophore,introduces an acryloyl group as thiol binding site,we synthesized a turn-on fluorescent probe 4-1 for discriminating detection thiols,hydrogen sulfide and sulfite via two emission channels.Among them,Cys,Hcy and GSH had a nucleophilic addition mechanism,while H2S and SO32-have a nucleophilic addition-cyclization mechanism.This probe successfully detects H2S/SO32-and biothiol in B16 cells through two emission channels,and has the ability to detect exogenous H2S in living mice...