Synthesis And Properties Of Fluorescent Probes For Detecting ONOO^-,Hg²⁺/SO₂ And HClO

Biologically active species play an important role in the regulation of redox homeostasis and signal transduction,including reactive oxygen species(ROS),reactive nitrogen species(RNS)and reactive sulfur species(RSS),etc..Monitoring the generation,distribution,accumulation and dynamic fluctuation of these active species in biological systems has always been one of the current research hotspots in the field of chemicobiology.In recent years,due to the advantages of high sensitivity,simple operation,fast reaction speed,and relatively low cost,fluorescent probes have been used in combination with fluorescent confocal microscopes to achieve real-time imaging in living cells and become a powerful tool for visualization of biomolecules.For this reason,we designed and synthesized four reaction-based fluorescent probes for the detection of ONOO-,Hg2+/SO2 and HClO in this paper,and further studied their spectral properties.A fluorescent probe SX-1 for detecting ONOO-was designed and synthesized based on triphenylamine and benzoindocyanine dye.The probe can selectively recognize ONOO-,and the color of the solution changes from blue to light blue,enabling naked eye detection.In addition,the probe SX-1 has the advantages of good photostability,wide pH range,strong anti-interference ability and good biocompatibility.It has been successfully applied to the detection of endogenous and exogenous ONOO-in HeLa cells.A near-infrared ratiometric fluorescent probe SX-2 for detection of ONOO-was synthesized based on the hemicyanine dyes.The probe has the advantages of good selectivity,fast response speed(15 s),naked eye detection,large emission wavelength shift(260 nm),etc.,and has been successfully applied to the ratio fluorescence imaging of exogenous ONOO-in Hela cells.Based on the hemicyanine dyes,the mitochondria-targeted dual-function Hg2+/SO2 fluorescent probe SX-3 was designed and synthesized.On the one hand,the probe can respond quickly(100 s)to SO2 and exhibit blue fluorescence enhancement.Meanwhile,the solution showed a clear blue-violet color change to light blue before and after reaction with HSO3-,which can be identified with the naked eye.On the other hand,the dimethylaminothioformyl ester group can respond to Hg2+ and show nearinfrared fluorescence emission.The spectral response performance has been introduced in the previous work of our research group.Therefore,the probe SX-3 was used as a dual-function fluorescent probe to detect Hg2+ and SO2,and it showed its ability to detect Hg2+ and SO2 in Hela cells.Based on the coumarin fluorophore,a fluorescent probe SX-4 for detecting HClO was designed and synthesized.The probe was easy to synthesize,has good photostability in buffer solution mixed with MeCN and PBS(v/v=3:7,10 mM,pH=7.4),and showed specific recognition of HClO.In addition,the probe SX-4 has strong anti-interference ability and large stokes shift(110 nm).