Sensitive Detection And Imaging Of Endogenous Peroxynitrite Using A Benzo[d]thiazole Derived Cyanine Probe

Peroxynitrite is a short-lived endogenous reactive species and plays important roles in many physiological and pathological processes.In this work,we synthesized a near-infrared probe based on the structure of benzothiazole derived cyanine for determination of peroxynitrite(ONOO").The designed probe specifically reacted with ONOO" through oxidative cleavage of conjugated C=C double bonds and generating the non-fluorescent product.Meanwhile,the characteristic absorption of the probe at 600 nm greatly decreased after reaction with ONOO-,accompanied by drastic color change from bright blue to green yellow,which exhibited a distinct visual feature.It was demonstrated that the probe could be used to measure ONOO-in a dose-response manner and had a detection limit lower as 26 nM.Furthermore,the probe Cy-SN was applied for the imaging of endogenous ONOO-in living cells by confocal microscopy,which showed good cell permeability and low cytotoxicity.Successful application of probe for exogenous colorimetric detection and endogenous fluorescence imaging of ONOO-is suggesting its great potential applications in biological analysis.The first chapter introduces the properties of peroxynitrite anion and its properties and interactions of nitric oxide and superoxide anion radicals associated with its synthesis in cells.A method for detecting peroxynitrite anion,including spectrophotometry,chemiluminescence,electron spin resonance,electrochemical analysis,and fluorescence spectroscopy.In the fluorescence spectroscopy,organic fluorescent probes for detecting peroxynitrite anions,including fluorescein,rhodamine;BODIPY and cyanine,are introduced.In the second chapter,we designed and synthesized a novel organic molecule fluorescent probe Cy-SN based on the cyanine structure Cy5 and modified with a benzothiazole group.We will not introduce the detailed and synthetic steps and pass the mass spectrometry.It is characterized by nuclear magnetic resonance spectroscopy.We studied the spectral properties of the probe,the fluorescence intensity of the fluorescent probe Cy-SN and its response to peroxynitrite anion under different pH conditions,and the spectral detection of different concentrations of ONOO-by the fluorescent probe Cy-SN.And the detection limit of the probe to ONOO-was 26 nM.In addition,we also explored the selectivity of the probe Cy-SN for ONOO-and its detection mechanism.Finally,we used this probe for the detection of endogenous and exogenous ONOO-in living cells and fluorescence imaging of the probe,which showed low cytotoxicity and good cell imaging performance.Therefore,it has a good application prospect.