Design,Synthesis,and Property Studies Of BODIPY-based Reactive Fluorescent Probes For Hypochlorous

As a kind of reactive oxygen species(ROS),hypochlorous acid plays an important role in physiological and pathological processes.Scientific research shows that endogenous hypochlorous acid is closely related to many diseases.It is necessary to develop effective tools and means for detecting hypochlorous acid which may be used for biological research.In recent years,the fluorescence probe method has attracted wide attention from scientists due to its advantages such as high sensitivity,high selectivity,and easy operation.Among many organic fluorescent dyes,BODIPY dyes have a good advantage,which have been choosen as a precursor to synthesize hypochlorous acid fluorescent probes in this paper.Although many hypochlorous acid fluorescent probes have been reported,they still face two major problems: 1.The emission wavelength of most hypochlorous acid fluorescent probes is in the visible light region,and the detection of hypochlorous acid by near-infrared light is so fewer,which to some extent limits the application of hypochlorous acid fluorescent probes in life science.2.Mitochondria are the sites where intracellular hypochlorite is produced,however,pathogenic mechanism of hypochlorous acid is not yet clear.It is a challenge to explore water-soluble probes that can target mitochondria.In order to solve the above problems,two types of reactive hypochlorous acid fluorescent probes were designed and synthesized,including aldoxime-based and thioether-based.The spectral properties of the fluorescent probes were characterized.The results are as follows:To prolong the emission wavelength of hypochlorous acid fluorescent probes,probe 1 and probe 2were designed and synthesized,by changing the conjugated system of BODIPY dyes and introducing an aldoxime group as recognition group at 8-position.The two probes achieve detection of hypochlorous acid in the visible and near-infrared regions respectively,whose significant advantage is able to quickly detect hypochlorous acid.Moreover,the two probes have no response to other active oxides and nitrides exceptfor hypochlorous acid,whose detection limits are 7.97 nmol and 4.45 nmol,respectively.They present good fluorescence intensity over a wide pH range(6 to 10).Finally,we will use cell imaging to explore whether or not probe 2 can recognize intracellular hypochlorous acid and we also expect that will have potential applications in bioimaging.To explore the activity of the 4-position of BODIPY and the ability to quench the fluorescence when the fluorine atom was substituted,the probe 3 was designed and synthesized.Through the nucleophilic substitution reaction,thioether was introduced into the 4-position of BODIPY.On this basis,we modified the pyridinium group at the 8-position of BODIPY,and synthesized a water-soluble hypochlorite fluorescent probe 4,which achieved a specific recognition detection of hypochlorous acid.Their spectroscopic properties have been studied so far.Then,we need apply probe 4 to Hela cells in the hope of achieving targeted mitochondrial and detecting effects of endogenous hypochlorous acid ions.