The Design,Synthesis And Application Of Fluorescent Probe For Detection Of Redox Reactive Sulfur,Reactive Oxygen Species And PH

Redox homeostasis in biological systems and the relative stability of microenvironmental pH are the physiological basis for the survival and development of organisms.Reactive sulfur species(such as Cys,Hcy,GSH,and H₂S)and reactive oxygen species(such as H₂O₂)are redox couples that are abundant in cells,and they maintain the redox homeostasis and normal cell metabolism.Abnormal changes in the content of the medium can cause cardiovascular disease,diabetes,Alzheimer's disease and other related diseases.At the same time,the relatively stable pH of the lysosome in cells maintains the normal function of the lysosome,and abnormal pH changes can cause lysosomal dysfunction,leading to cell necrosis and apoptosis.Therefore,real-time monitoring of redox homeostasis in cells and changes in pH of the lysosomal microenvironment are of great significance for understanding the relevant pathological and physiological processes.The main results are shown as follows:1.Using the single-atom replacement strategy,a fluorescent probe A based on the ICT mechanism was designed and synthesized to simultaneously distinguish and detect Cys/Hcy and GSH in cells.The probe has greatly improved the spectroscopic properties of the probe by replacing the oxygen atom in NBD-Cl with a selenium atom with a larger radius and stronger charge-carrying capacity,and successfully applied to fluorescence imaging analysis of endogenous and exogenous Cys/Hcy and GSH in living cells.2.A dual-function fluorescent probe B based on the FRET mechanism was designed and synthesized,which can distinguish and detect the redox signal molecules H₂O₂ and H₂S in cells at the same time.The probe uses borate and azide groups as the recognition sites for selective detection of H₂O₂ and H₂S,and uses coumarin and1,8-naphthalimide as energy donors and acceptors to construct a FRET mechanism.The effect of detecting H₂O₂+H₂S is achieved.This probe has been applied to fluorescence imaging analysis of endogenous and exogenous H₂O₂,H₂S and H₂O₂+H₂S in living cells.3.A fluorescent probe C based on PET mechanism was designed and synthesized for real-time monitoring of pH in lysosomes.The probe uses1,8-naphthalimide as the fluorophore,the morpholine group as the fluorescence quenching group,the pH sensor module and the lysosomal targeting group(the pKa value in response to pH is 6.019,The linear range is 4.96-6.87).Under acidic conditions,the protonation of the nitrogen atom of the morpholine unit hinders the PET mechanism,and the fluorescence signal of the probe gradually increases as the pH decreases,thereby achieving the effect of real-time monitoring of the pH in the lysosome.