Design,Synthesis And Application Of Reaction-based Fluorescent Probes For The Detection Of Bioactive Small Molecules

Bioactive small molecules?BSMs?play crucial roles in physiological processes.Abnormal levels of these species in vivo can cause diseases.People's living environment and food also contains of BSMs?Sulfur/nitrogen oxides in the atmosphere and additives in food?.An excess amount of these species in the atmosphere or food can cause discomfort feeling and leading serious diseases.To guarantee people's health,it is very necessary to develop novel analysis methods for the detection of BSMs in environment,food and physiological or pathological processes.Fluorescent probe has attracted great interest due to simple operation,high sensitivity,good selectivity,fast response,high temporal and spatial resolution,negligible damage and realtime visualization in situ monitoring.In this thesis,we have developed some fluorescent probes for the detection of sulfur dioxide?SO₂?derivatives,biothiols,formaldehyde?FA?as well as hypochlorite?ClO-?,and then performance of practical application and bioimaging were studied.The main contents were summarized as follows:?1?A ratiometric fluorescent probe?BIFS?for SO₂ derivatives has been developed based on the conjugate of pentafluorobenzaldehyde and benzo[e]indolium.Upon nucleophilic addition reaction to the ?-conjugation of the probe,a significant colorimetric and ratiometric fluorescence dual response towards SO₂ derivatives was observed.The probe was successfully used for detection and fluorescence imaging of SO₂ derivatives in living cells.?2?A near-infrared fluorescence-enhanced probe?CFL-O-NBD?for simultaneously discriminative detection of cysteine?Cys?and glutathione?GSH?was constructed by combining nitrobenzofurazan?NBD?with a cyanine-based fluorophore via an ether bond,which would be substituted by nucleophilic biothiols,while Cys would induced an intramolecular rearrangement reaction on electrophilic site of NBD.Cys could be easily identified by the simultaneous appearance of two emissions,whereas GSH could be characterized by the generation of single emission.The probe has been successfully employed to detect biothiols in human plasmas and living cells.?3?A naphthalene-based fluorescence-enhanced probe?AENO?for FAwas successfully synthesized.Homoallylamino can react with FA,then 2-aza-Cope rearrangement and hydrolysis occurred.Thus,significant color changed and fluorescence enhancement could be observed after reaction with FA due to the internal charge transfer.The probe might be used as a promising tool for the detection of FA in food and living cells.?4?A near-infrared fluorescent probe?CMBI?for hypochlorite?ClO-?based on the conjugate of coumarin derivative and benzo[e]indolium,which displayed colorimetric and ratiometric fluorescence dual response towards ClO-by oxidation reaction to interrupt ?-conjugation and the internal charge transfer.Fluorescence co-localization studies demonstrated that the probe localizes specifically in the mitochondria,which could be used for real-time monitoring intracellular ClO-in living cells by ratiometric fluorescence imaging.In summary,four types of reaction-based fluorescent probes for BSMs were designed and synthesized,and all of them displayed excellent properties.These probes have potential applications in the field of environmental monitoring,food detecting,physiological or pathological research,etc.