Synthesis And Application Of Fluorescent Probe For Detecting Hypochloric Acid And Cysteine

Small molecule fluorescent probes have attracted the interest of researchers in many fields because of their unique properties such as controllable structure,good specificity,and visual detection.However,the developed fluorescent probes still have some shortcomings.Firstly,the detection of analytes with large structural similarity is easily interfered.Secondly,the self-absorption of biological samples makes the fluorescent probe with short wavelength unsuitable for deep imaging in tissues and living bodies,which limits its further application in biological system.Thirdly,the real-time,in-situ,dynamic and accurate monitoring of bioactive molecules in subcellular microenvironment still has some shortcomings,such as low stability and unsatisfactory anti-interference ability.Therefore,in order to realize the specific detection of active substances in biological samples and study the imaging of active molecules at subcellular level,three different types of small morecule fluorescent probes were desighed and synthesized,to develope the detection methods of Cys and HCl O,and the response mechanism of probes to active molecules was studied.The details are as follows:(1)Based on the addition-cyclization reaction between cysteine(Cys)and acrylate groups,a green-emitting Cys fluorescent probe(E)-2-(2-(benzo[d]thiazol-2-yl)-2-cyanovinyl)-5-(diethylamino)phenylacr ylate(BTIC-Cys)was developed.The acrylate group in BTIC-Cys molecular structure has strong electron pulling ability,which hinders intramolecular charge transfer(ICT)process,leading to the quenchment of fluorescence.After adding Cys,acrylate group leaves,hydroxyl group is released,The hydroxyl group reacts with the cyano group to form a ring,and the fluorescence recovery is restored.realizing,the detection of Cys.The linear range of Cys detection by probe is 0-90 μM,and the detection limit is 208 n M(S/N =3).In the presence of homocysteine,glutathione and other biological mercaptans,BTIC-Cys realized the specific detection of Cys in human serum,and achieved good recovery rate.(2)Based on the oxidative cleavage reaction between hypochlorous acid(HCl O)and dimethyl thiomethyl ester(DMTC),a red-emitting fluorescent probe O-(4-(2,2-diacetonitrile)-2,3-dihydro-1-hydrogen-anthracene-6-yl)dimethyl amino thiomethyl ester(HM-OCl)was designed and synthesized.The DMTC and malononitrile in HM-OCl molecular structure are electron-withdrawing groups,which hinder ICT effect and quench fluorescence.When HCl O solution is added,DMTC part of HM-OCl undergoes oxidative cleavage reaction,releasing hydroxyl groups,recovering ICT effect and enhancing fluorescence,thus realizing near infrared fluorescence detection of HCl O.When S/N = 3 and the linear range of HCl O concentration detection is 0-70 μM,the detection limit is 445 n M.HM-OCl was successfully applied to fluorescence imaging analysis of exogenous HCl O in cervical cancer cells(He La).(3)Based on phenylsulfonamide,a fluorescent probe targeting Golgi apparatus to detect HCl O was developed.When HCl O solution was added,the DMTC part of probe O-(1,3-dioxo-2-(4-sulfamoyl phenyl)-2,3-dihydro-1H-benzo [de] isoquinolin-6-yl)dimethyl carbamate(Gol-OCl)undergoes oxidative cleavage reaction,hydroxyl groups were released,ICT effect was restored,fluorescence was enhanced,and in situ real-time detection of hypochlorite in Golgi apparatus was realized within5 s.When S/N = 3 and the linear range of HCl O concentration detection is 0-70 μM,the detection limit is 212 n M.Gol-OCl has high sensitivity,good selectivity,low cytotoxicity and good co-localization effect on Golgi apparatus.The probe has been successfully applied to fluorescence imaging analysis of HCl O in macrophage Golgi apparatus.