Design And Synthesis Of Novel Fluorescence Probes For Biosensing Application

After entering 21 century,with the continuous development and progress of analytical chemistry,organic chemistry,material chemistry and biochemistry etc.,the integration of various disciplines has become a hot spot and trend in scientific research.Fluorescence probes,as a product of this integration,are an indispensable tool in chemo/biosensing technology,widely use in environmental monitoring,food analysis,clinical analysis,biological analysis,life sciences etc.Owing to distinct advantages of the organic small molecule fluorescence dyes,such as small-size,flexible design,controllable synthesis,easy structural modification,low toxicity etc.,it has broad application prospects and become the important materials for fluorescence probes.In this dissertation,we have employed some organic small molecule fluorescence dyes,designed and synthesized a series of novel fluorescence probes.They have been used for detection of the environmental and food contamination,the significant bioactive enzyme in clinical and so on,and tested their fluorescence imaging application capability in living cells and tissues.The main research contents are as follows:1)In the Chapter 2,we have designed and synthesized a novel fluorescence probe(Naphsulf-O)for detection of hydrazine based on the nucleophilic aromatic substitution(NAS)reaction.This probe was conveniently prepared by protecting the hydroxy group of 6-acetyl-2-hydroxynaphthalene via O-4-nitrobenzenesulfonylation.Upon NAS of hydrazine toward this probe,this protecting group was removed and fluorophore was released,realizing the detection of this probe to hydrazine.The tested results indicated that probe Naphsulf-O possessed a large Stokes shift(?140 nm),high selectivity and sensitivity,and the limit of detection was 0.716 ppb(22 nM).Furthermore,this probe was successfully applied to detection and imaging of hydrazine in living cells.2)In the Chapter 3,with naphthalene derivatives as the parent,we have designed and synthesized a novel mitochondria-targeted near-infrared fluorescence probe(NDMBT)for the ratiometric detection of SO2 derivatives on the basis of nucleophilic addition.In vitro experimental results illustrated that the response time of the probe toward SO2 derivatives was uitrafast(?10 s),and the linear response range reached 0-90 ?M.Living cell imaging results also manifested that the probe possessed the capacity for detection and imaging sulfur dioxide derivatives in the mitochondria of living cells.3)In the Chapter 4,we have established a generally applicable strategy for developing activity localization fluorescence(ALF)peptide probe based on thiol-ene click reaction.The ALF probe was synthesized by a facile thiol-ene click reaction of a cysteine-appended peptide with an acryloylated fluorophore.Upon cleavage by peptidase,the probe underwent a seven-membered intramolecular cyclization and released this fluorophore with the excited-state intramolecular photon transfer(ESIPT)effect.This probe is demonstrated for detection of Caspase-8 activity,and employed the insoluble fluorophore(2-(5'-Chloro-2-Hydroxylphenyl)-6-Chloro-4-(3H)-Quinazolinone,CHCQ)with ESIPT effect.In vitro assays demonstrated that ALF probe afforded high selectivity and sensitivity for Caspase-8 detection.Living cell imaging revealed that our probe was able to render highly localized and high-resolution fluorescence signal for Caspase-8.4)In the Chapter 5,with coumarin derivatives as the parent,we have designed and synthesized a novel fluorescence probe(Cascade Reaction Probe,CRP)for the background-free detection of nitroreductase(NTR)based on a cascade reaction.Upon cleavage by NTR,CRP was formed a larger conjugated system with the strong fluorescence through this reaction,which enabled high selectivity,high sensitivity and background-free detection and imaging of NTR in living cell.5)In the Chapter 6,a ratiometric ?-Glutamyltranspeptidase(GGT)-selective two-photon fluorescence probe(gGlu-AANA)has been designed and synthesized based on the naphthalene derivatives with two-photon characteristics.This probe effectively eliminated the effect of the environmental factors,and improved the sensitivity for detection of GGT.At the same time,by means of two-photon characteristics of the naphthalene derivatives,this probe has been successfully applied to image and detect GGT in living cells and tissues.Moreover,the assay results of human serum samples implyed that the probe was practically useful for the detection of GGT in clinical.