NIR Fluorescence Probe Based On ICT Mechanism For The Detection Of Inflammatory Process ONOO~-

Nitrite peroxide(ONOO~-)is an important bioactive substance,which maintains the intracellular redox balance,exhibits antibacterial activity,and plays an important role in cell signal transduction.However,due to its high oxidation and nitrification capacity,excessive ONOO~-can destroy a variety of biomacromolecules and induce diseases,including cancer and inflammation.The biological half-life of ONOO~-is very short,about 10 ms,and the intracellular homeostatic concentration of this substance is within the range of nanomole,so it is not easy to accurately measure by conventional detection methods.Fluorescence analysis technology has been recognized by scholars as a more effective detection tool due to its advantages of high sensitivity,simple structural modification and visualization.Based on this,we synthesized a series of NIR fluorescence probes through reasonable design to study the production of ONOO~-and its role in the inflammatory process.The specific work is as follows:(1)Based on the intramolecular charge transfer mechanism,a NIR fluorescence probe HCY-PN with mitochondrial targeting function was reasonably designed.With boric acid group as the ONOO~-recognition site,probe HCY-PN can quickly identify the target in PBS buffer solution,and the fluorescence enhancement of probe maintains a good linear relationship with ONOO~-concentration,and the detection limit is 11.2 n M.Probe HCY-PN can eliminate interference from metal ions,active sulfides and other reactive oxygen species to accurately identify ONOO~-while maintaining a stable response across the pH range.In view of the excellent response performance and low cytotoxicity of the probe HCY-PN,we successfully detected the changes of endogenous and exogenous ONOO~-concentrations in cells.(2)Through structural optimization,a ratio type NIR fluorescence probe was designed for the detection of ONOO~-in the inflammatory process.By introducing halogen atoms,the probe HDM-Cl-PN can obtain higher quantum yield,longer fluorescence emission wavelength,higher fluorescence response ratio and better pH stability.The probe HDM-Cl-PN has a very good imaging effect.The dual-channel fluorescence emission can eliminate the influence of the probe concentration fluctuation and external test conditions including the detector voltage on the test results.Meanwhile,the large Stokes shift of the probe itself further reduces the background interference.HDM-Cl-PN was used to detect the fluctuation of intracellular ONOO~-concentration.With the increase of endogenous or exogenous ONOO~-concentration,the fluorescence ratio of red channel and yellow channel of the probe changed.In vivo imaging of mice with LPS-induced peritonitis,significant ratio changes in the probe revealed ONOO~-production during inflammation.