Detection Of Active Sulfides In Cells/in Vivo Based On Molecular Probes

Fluorescent probe refers to the fluorescent substance who responds specificly toward the analyte through the reaction or combination.Fluorescent probe includes mainly the organic molecular probe,luminescent nanoparticle,molecular beacon and so on.Fluorescent probe can be used in environmental detection,dangerous material analysis,and cell or invio imaging.Hydrogen sulfide?H₂S?has the active chemical properties,including the strong reducibility and the coordination effect etc.As an important signaling molecule,H₂S plays the indicative role in diagnosing the diseases of central nervous system.The other signaling molecule,sulfur dioxide?SO₂?existing with the form of HSO₃^-,has the antibacterial,antimicrobial and antioxidative properties.It is found that HSO₃^-serves as a messenger in the system of cardiovascular.Therefore,it is an urgent need to develop a method for real-time monitoring the change of intracellular/biological SO₂ or H₂S.In this paper,several fluorescent probes have been designed to detect hydrogen sulfide and sulfur dioxide in living system.The main contents are as follows:Chapter 1:It describes the luminescence principle of fluorescent probe,the influencing factors for fluorescence molecules and the luminescence mechanism.Besides,this chapter discribes the brief introduction for the background about SO₂and H₂S,and summarizes the current defects in probe design.Chapter 2:It introduces the synthesis of fluorescence probes?E?-4-?3-formyl-4-hydroxystyryl?-1-methylpyridin-1-iodide?FHMI?and its related properties.This probe can overcome the problem that nucleophilic reaction breaks the conjugate system of the electron base.The probe is a small,delicate molecule containing a hydroxyl group as the electron donor,an aldehyde group as the electron acceptor,and a pyridinum group as the other electron acceptor.When sensing SO₂,the aldehyde group react with SO₂,changing the electron push-pull from the triangular relation to the direct relation and thus triggering the fluorescence.The pyridinum salt structure can make FHMI accumulate in the mitochondria.Hydroxy structure can increase hydrophilicity to make the probe FHM soluble in water.FHMI shows the fast response?within 1 min?,detection limit?13.1 nM?,low toxicity and fluorescence imaging in the cell system.Chapter 3:It introduces the synthesis of fluorescence probes?E?-1-?2,4-dinitrophenoxy?naphthalen-1-yl)-2-?4-nitrophenyl?diazene?PR-H₂S?and its related properties.The reaction moiety of this probe is the 2,4-dinitrofluorobenzene,which has the specific recognition on hydrogen sulfide.Because the strong absorption of 2,4-dinitrofluorobenzene can quench the fluorescence,it eliminates the interference from the molecular background of fluorescent probe its self.The2,4-dinitrofluorobenzene structure react rapidly with H₂S and thereby triggered the fluorescence.Because of the strong reductive properties of H₂S,it makes the nitro deacidized,and also reduces the damage caused by the fluorophore.Fluorescent probe PR-H₂S is succesfully used in living cells because of its high sensitivity,good selectivity and low toxicity?cell survival rate>90%?.Chapter4:Itdescribesthesynthesisoffluorescenceprobe?E?-4-?6-?2,4-dinitrophenoxy?naphthalen-2-yl?vinyl)-1-methylpyridin-1-idium?EMII-H₂S?and its application.The nitro?strong electron-withdrawing groups?helps to make the fluorescence quenched,which is favorable to eliminate the background interference.This probe can react selectively and quickly with H₂S.Moreover,the pyridinum salt moiety can help the EMII-H₂S probe accumulate into mitochondria.Fluorescence probe EMII-H₂S can be used for fluorescence imaging in living cells with the aid of its advantages,such as mitochondrial targeting,high selectivity,rapid reaction and small toxicity.Chapter 5:It makes a summary of the whole text.At the same time,it summarizes the importance for the detection of endogenous hydrogen sulfide and the sulfur dioxide in living systems.Also this chapter demonstrates the necessity to seek the new probe for the detection of endogenous hydrogen sulfide and sulfur dioxide.