Design And Synthesis Of Aggregation-induced Emission Fluorescent Probes And Their Application In Detection

In sharp contrast to the traditional fluorophores that suffer from aggregation-caused quenching effect(ACQ),aggregation-induced emission(AIE)luminogens(AIEgens)are nonor low-emissive in good solvents but become strongly fluorescent after aggregation,which have emerged as a new generation of fluorescent probes with broad applications in various fields.Herein,two kinds of fluorescent probes with AIE characteristics have been designed,synthesized and utilized for the detection of the bio-enzymes and the toxic gases,respectively.1.The construction of turn-on AIE probe for leucine aminopeptidase(LAP)in living cells and tumor tissue:Abnormally expressed LAP is associated with diverse physiological and pathological disorders;hence it is of great importance to develop a highly selective and sensitive detection method for LAP.Herein,based on the AIE characteristics,a fluorescent light-up probe(DPA-TPE-Leu)has been developed for detecting LAP.In an aqueous medium,upon LAP-triggered enzymatic reaction,the recognition unit L-leucine amide moiety is cleaved from the probe molecule,resulting in the formation and aggregation of hydrophobic reaction product(DPA-TPE-OH)with AIE effect and thus giving out the turn-on green fluorescence.This probe has been effectively utilized in fluorescent imaging of endogenous LAP in living cells.In addition,it has been successfully applied for fluorescent imaging of HepG2 xenograft tumor.2.The construction of handy AIE-probe-based solid fluorescent test strips for ratiometric detection of gaseous nerve agents:Exposure to the odorless,colorless,tasteless and yet lethal nerve gases could lead to paralysis of the central nervous system,organ failure or even rapid death.Hence it is significantly meaningful to develop a portable detection method for these gaseous nerve agents.Herein,based on the AIE characteristics,a fluorescent probe(DPA-TPE-Py)for gaseous nerve agent simulant---diethyl chlorophosphate(DCP)has been developed.It is easy to afford the handy and portable DPA-TPE-Py-based fluorescent test strip via direct deposition of AIE probes onto the filter paper.When exposed to DCP vapor,the reactive group of the probe molecule,the pyridine group(Py),will nucleophilically attack the strong electrophilic phosphonyl group of DCP and ultimately form the pyridinium salt DPA-TPE-PyH,making the fluorescence of the test strips change from yellow to orange red and the emission wavelength red shift from 546 nm to 624 nm,thus enabling rapid ratiometric fluorescence detection of DCP.