Design,Synthesis,and Fluorescence Imaging Study Of Fluorescent Probe For Sensing Hydrogen Cyanide,as Well As Fluorescent Probe For Simultaneously Sensing Thiols And Primary Aliphatic Amines

Hydrogen cyanide(HCN)is a recognized toxin.For human blood,HCN concentrations higher than 20 ?M are considered toxic.At the subcellular level,the mitochondria are recognized as being the primary site of HCN toxicity.It has also been suggested that HCN is generated within neurons and plays an important role in the central nervous system of the brain.Therefore,it is of great significance to develop a high selectivity and high sensitivity probe to monitor HCN levels in mitochondria.Biological thiols play essential roles in cellular growth and maintaining redox homeostasis.Abnormal levels of cellular thiols have been implicated in a number of health conditions,including cancer,neurodegenerative disorders,and cardiovascular diseases.On the other hand,primary aliphatic amines(PAA)such as dopamine,serotonin,noradrenaline,and histamine act as neurotransmitter,performing crucial roles in interneuronal chemical communication.Particularly,biological thiols and PAA exert interplaying roles in complex biological events.So it is important to develop a fluorescent probe that can concurrently identify both biological thiols and PAA.Herein,we rationally designed and developed a ratiometric fluorescent probe for sensing mitochondrial HCN and a fluorescent probe for simultaneously sensing both thiols and PAA.The specific works are as follows:1.We have prepared and characterized a mitochondria-specific ratiometric fluorescence probe for HCN.This probe relies on 7-diethylamino-coumarin as the fluorophore,phenyl conjugated 1-methylenepyrrolidinium group as both recognition unit for HCN and mitochondria targeting unit,and benzyl chloride group as immobilization unit within mitochondria.Photophysical and spectral characterization studies revealed that the fluorescent probe reacts rapidly(within 1 s)and responds reversibly to HCN with both high selectivity and sensitivity(the detection limit is 65.6 nM).Notably,the fluorescent probe is retained in the mitochondria even when the mitochondria membrane potential is decreased.It can be used to visualize different concentration of exogenous HCN within the mitochondria of HepG2 cells and proved effective in monitoring fluctuations in endogenous HCN concentrations within the mitochondria of PC12 cells and neurons.2.We rationally constructed a fluorescent probe for sensing thiols and PAA in distinct fluorescence channels.The 7-diethylamino-coumarin dye was used as fluorophore,while the electron deficient 1-methylenepyrrolidinium moiety(non-phenyl conjugated)was employed as specific recognition unit for both thiols and PAA.The optical experiments indicated that the fluorescent probe itself exhibited fluorescence in the red channel.After treatment with thiols and PAA respectively,the fluorescent probe exhibited its response in blue fluorescence channel and green fluorescence channel correspondingly.Furthermore,in the presence of both thiols and PAA,the fluorescent probe can sequentially respond to thiols and PAA.The practical utility of the fluorescent probe for sequential sensing thiols and PAA in human blood serum has been successfully demonstrated.In addition,the fluorescence imaging experiments showed that the fluorescent probe can be applied for sequentially sensing endogenous thiols and PAA in living cells.Moreover,sequential tracking of the levels of antihypertensive drugs captopril and amlodipine in living cells also has been performed.