Study On Coumarin-Based Fluorescent Probes For Biologically Active Species And Microenvironmental Detection

The biologically active species and microenvironment play an important role in maintaining the balance of life activities.Therefore,designing effective analysis tools for the detection of biologically active species or microenvironments is of great significance.The small-molecular fluorescent probes are widely used in fields of medical biology,environmental protection,chemical detection due to their advantages of convenient operation,good selectivity,high sensitivity,good biocompatibility,and realtime detection in a biological environment.In this thesis,four fluorescent probes for detecting biologically active species and microenvironment were constructed based on coumarin,and these probes provided some new identification and diagnosis methods for detecting diseases in the living system.The main research work is as follows:1.A near-infrared ratiometric fluorescent probe NIR-RSF for reversible detection of bisulfite and formaldehyde based on coumarin and keto acid was constructed.Probe NIR-RSF displays an ultrafast response to bisulfite,and has high sensitivity and selectivity.After NIR-RSF identification of bisulfite,and it reversibly reacts with formaldehyde to restore the probe’s fluorescence.The probe has good reproducibility for reversible detection of bisulfite and formaldehyde.And NIR-RSF shows good mitochondria targeting ability,and can detect exogenous and endogenous bisulfite and formaldehyde in cells and mice.This work provides a new detection tool for monitoring the content fluctuations of bisulfite and formaldehyde in vivo.2.A multifunctional probe MGV that can be used to detect mitochondrial glutathione and viscosity changes simultaneously based on coumarin and pyridine salt was constructed.MGV exhibits high selectivity and sensitivity toward glutathione,accompanied by colorimetric and ratiometric fluorescence signal changes.MGV has low cytotoxicity and good mitochondria-targeting ability,and it can be used for dual-channel fluorescence imaging of endogenous/exogenous glutathione in live cells.MGV can also be used to track the changes of viscosity in cells,and the formation of mitochondrial donut bleb vesicles and apoptosis can be visualized and observed by MGV.What’s more,MGV can distinguish between normal cells/tissues and cancer cells/tissues by dual-channel fluorescence.this work provided a smart versatile probe for glutathione,viscosity,apoptosis,and tumor imaging.3.The first membrane and Golgi-targetable fluorescent probe for in-situ detection of peroxynitrite based on coumarin and indole salt was constructed.The probe was prepared by linking a sulfanilamide moiety for targeting Golgi and was found capable of real-time detection of peroxynitrite.Moreover,MG-ONOO shows excellent sensitivity and selectivity ability,which is beneficial for fluorescence imaging of endogenous/exogenous peroxynitrite in live cells.In addition,MG-ONOO can be used to assessing APAP-induced hepatotoxicity and its remediation in mice.This work offers a new detection tool for a deeper understanding of Golgi oxidative stress and drug-induced liver injury.4.Two membrane-targeted polarity-sensitive fluorescent probes MEMs based on tetrahydroquindox coumarin were constructed.Probe MEMs have the advantages of good water solubility,strong red fluorescence in low-polarity media,large Stokes shift,good photostability,low cytotoxicity,excellent cell membrane targeting ability,and can be used as an effective polarity-sensitive probe.MEMs can specifically light up cancer cell membranes with bright,long-termed red fluorescence with a wash-free process.This is the first report that polarity-sensitive fluorogenic probes can specifically illuminate cancer cell membranes and tumours,which provides new insights to understand cancer cells and cancer diagnosis.