The Design, Synthesis And Application Of Fluorescent Probes For Detection Of Reactive Sulfur Species

Cysteine?Cys?,homocysteine?Hcy?and glutathione?GSH?are the most abundant small molecule thiol-containing amino acids?biothiols?in mammalian cells.Though they have the similar structures and chemical reactivity,their concentrations and biology functions in cells or serum are totally different.Abnormal levels of biothiols could result in cardiovascular disease,Alzheimer's disease and imbalance of cellular redox homeostasis.The metabolite of Cys,sulfur dioxide?SO₂?,plays an important role in protection of the cardiovascular system and antibacterial.Therefore,it is of great significance to develop reliable fluorescent probes to distinguish and quantify biothiols in cells or serum,and monitor their production,dynamic and metabolism in real-time.The main results of this dissertation are shown as follows:1.We have designed and synthesized a dual-emission and mitochondria-targeted fluorescence probe Mito-PTB for sensing of SO₂.Based on intramolecular charge transfer?ICT?and aggregation-induced emission?AIE?process,the goals of dual-channel fluorescence enhancement and mitochondrial targeting are achieved by integrating phenanthroimidazole and cyanine moieties.The probe Mito-PTB could detect SO₂ derivatives quickly and sensitively,and emit blue and red fluorescence at450 nm and 605 nm under different excitation wavelengths.Dual-color fluorescence imaging of mitochondria SO₂ derivatives in living cells was alao achieved successfully.2.We have designed and synthesized a multi-signal fluorescent probe BCC with multiple binding sites for simultaneous differentiation of cysteine?Cys?,homocysteine?Hcy?,and glutathione?GSH?in the advantage of the differences of the steric distances between thiol and amino group in biothiols.The probe BCC was synthesized by integrating 4-chlorinated coumarin and benzothiazolylacetonitrile,which was equiped with four binding sites with different spatial distances for simultaneously differentiate Cys(?_ex/?_em=360/457 nm),Hcy(?_ex/?_em=480/559 nm)and GSH(?_ex/?_em=400/529 nm).This probe was successfully applied to the fluorescence imaging of endogenous Cys and GSH and exogenous Cys,Hcy,and GSH in living cells.3.We have designed and synthesized a multi-signal fluorescent probe 1 for simultaneous visualization of endogenous Hcy,Cys,GSH and their transformation in living cells.Using coumarin as a fluorophore,This probe is featured with the N,N-dipropylamino ring structure and ethyl acetate group,which could improve its fluorescence quantum yield and water-solubility,respevtively.This probe exhibited high sensitivity and high selectivity for distinguishing Hcy(?_ex/?_em=375/467 nm),Cys(?_ex/?_em=400/503 nm)and GSH(?_ex/?_em=500/568 nm).And it was successfully applied to the simultaneous discrimination and visualization of endogenous Hcy,Cys,GSH,and their transformation in living cells.