Design,Synthesis And Application Of Organic Fluorescent Probes

On account of its ability to restrain the growth of bacteria and prevent mildew,bisulfite was widely used in food and drinks as preservatives and antioxidents.However,a high level of bisulfite can cause diarrhea,low blood pressure,allergies and asthma.Factory released a large amount of bisulfite in the process of industrial production and caused serious environmental problems.Some researches have proved that bisulfite produced in cytosols and mitochondria can regulate cardiovascular functions,such as lower blood pressure,relax blood vessels and the negative inotropic action of the heart.However,the abnormal level ofendogenous bisulfite is often associated with neurological diseases and lung cancer.As a result,many analytical approaches and techniques have been developed to detect bisulfites.Fluorescent probe provided a powerful tool for real-time sensing and biological visual perception because of its high sensitivity and spatiotemporal resolution,low cost and cytotoxity.Organic micromolecule fluorescentprobes that are used for the detection of analytes have been reported,but the practical application of samples and biological samples were relatively limited.As one of the reactive oxygen species,hypochlorous acid is used as thedisinfectant,deodorizer and bleachin our daily life.Most importantly,hypochlorous acidalso plays an important role in the physiological and pathological processes,which is known as the human firewall.However,it always leads to the incidence of inflammation,atherosclerosis,rheumatoid arthritis,respiratory diseases and cardiovascular diseases if the amount of hypochlorous acid is higher than the normal,thus bringing in serious harms to the body.Therefore,developingselective methodsof detecting hypochlorite is of great significanceto study cellular physiological and pathological processes.At present,methods of testing sulfite,sodium hypochlorite include spectroscopy method,electrochemistry,chromatography and capillary electrophoresis.Compared to other methods,fluorescence spectroscopy showed many advantages,such ashigh selectivity,sensitivity,easy preparation,simple instrumentation,real-time measurement,high spatial resolution and excellentbio-imaging.With the development of fluorescence imaging,small-molecule fluorescent probes havebecome important means of monitoring physiological processes in living cells.Rhodamine,coumarin derivatives have many advantages such as high fluorescence quantum yields,large Stokes shift.They are widely used as small molecularfluorescent probes viathe structural modification,thus emitting various bands of fluorescence.Based on the nature of the detectedanalyteand the optical properties of fluorophores,we designed and synthesized three probes to detect sulfite and hypochlorous acid,respectively and further studied their optical properties and application in biological cells.1 The synthesis,optical properties and application research of bisulfite fluorescent probe based on carbazole.We designed and synthesized a probe for the detection of bisulfite based on the carbazole moiety,with C=C bond as recognitiongroup.The probe behaved high selectivity and sensitivity toward bisulfite.The probe alone behaved red emission,while the fluorescence intensity significantly decreased after reactingwith bisulfite.The color changed from red to colorless under visible light.Fluorescence intensities and HSO₃^-concentrations can be described by a perfect linear regression relationship.The LOD was2.08×10^-66 M.The probe can be used to detect bisulfite in dry white wine and has great application value.2 The synthesis,optical properties and application research of bisulfite fluorescent probe based on coumarin.We designed and synthetized a coumarin fluorescent probe using the Michael addition reaction between the bisulfite and C=C bond.The probe behaved green fluorescence after the addition of bisulfite.The probe had good selectivity and fast response.3 The synthesis,optical properties and application research of hypochlorous fluorescent probe based on rhodamine.The probe was composed of imidazole[1,5-a]pyridine as donor and rhodamine as acceptor.Uponthe additionof HOCl,the oxadiazole in the probe was generated,resulting in the transformation of rhodamine moiety fromthe spirocyclic form to the ring-opening form,and then the TBET process took place.The probe exhibited low cytotoxity and high selectivity toward HOCl over other various anions and couldrespond to a low concentration of HOCl in the real time.Moreover,the probe can be used to detect exogenous and endogenous HOCl in living cells.