Design,Synthesis And Application Of Small Molecule Fluorescent Probe For Detection Of Cellular Redox Signal

The redox state of organisms is regulated and maintained by enzyme systems and biological active small molecules.These active small molecules mainly include reactive oxygen species(ROS),reactive nitrogen species(RNS)and reactive sulfur species(RSS),and their dysregulation will lead to the imbalance of the redox state,which will further lead to a series of pathological changes.Therefore,the development of detection techniques for these active small molecules is of great significance for the study of physiological and pathological mechanisms and the detection of diseasesAs emerging chemical biological detection techniques in recent years,fluorescent probes have the advantages of high spatio-temporal resolution,high specificity,low invasiveness,and easy modification capacity.Therefore,they have significant advantages in imaging biological active small molecules.However,in view of the active reactivity and low expression level of biologically active small molecules,how to improve the detection sensitivity of the probe is still a problem to be solved in the field of probe development.This thesis aims at the developing high-sensitivity small molecule fluorescent probes for important redox active species in organisms(GSH,ONOO~-)through the study of systematic structure-response relationship and the introduction of signal amplification strategies.Specific experiments are taken to confirm the feasibility of these two strategies.The thesis is mainly divided into two parts:1.Fluorescent probe for reductive small molecule GSH:In order to study the dynamic changes of endogenous GSH levels during neuronal development,the sulfoxide sensing moiety developed by our group has been used in building high-sensitivity fluorescent probes for GSH.Through the modulation of stereoelectronic effect and physicochemical properties of probe compounds,we have successfully developed a highly sensitive GSH probe,which gains 6335 folds fluorescence increase upon incubation 60min with GSH(400eq).Facilitated by this probe,we image and trace the intracellular GSH in neurons and investigating GSH flux throughout primary cortex neuron development,which further revealed the significant role GSH played in neuronal polarization.2.Fluorescent probe for oxidative small molecule ONOO~-:In this part,a series of probes are designed and synthesized by introducing signal amplification strategies using the ONOO~-responsive group phenylboronate.The effect of signal amplification strategies on improving the sensitivity of the probe response is initially explored.Responsive screening confirmed the effectiveness of the signal amplification strategy,and further evaluation confirmed that the probe has good response kinetics,concentration dependence,specificity,and pH dependence,thus has good biological application potential.