Design,Synthesis And Properties Of Water-Soluble Multifunctional Fluorescent Probes Based On Indolium Salts

Organic fluorescent probes have the advantages of rapid detection,simple processing,low detection limits,and biological applications.They have been widely used in chemical analysis,environmental detection,and biological imaging,and have been hot research topics in recent years.Most of the probes reported in previous studies have problems such as poor water solubility and high biological toxicity,which are difficult to use for image monitoring of specific substances in living organisms and cells.At the same time,most of them can only detect one substance,and it is difficult to pass one type Needle realizes the qualitative and quantitative of various substances.Starting from the detection of biothiols and harmful anions,a water-soluble near-infrared fluorescent probe with good detection ability for cysteine was prepared by combining a highly water-soluble indole sulfonium salt with a specific fluorophore.A water-soluble fluorescent probe capable of qualitatively and quantitatively detecting two substances of cyanate/sulfite and three substances of cyanide/sulfite/hypochlorite was also used.At the same time,combining the theoretical calculation and biological imaging experiments,the Detection mechanism and biological application.1.Hemicyanine was used as the fluorophore,acryl lipid was used as the recognition site,and indole sulfonium salt was used as the hydrophilic group.The conjugate addition-cyclization reaction of acrylate with cysteine was used to design and synthesize specific compounds.NIRHA,a near-infrared fluorescent probe for cysteine detection,has been examined in detail.The results show that the probe has excellent water solubility,and only 1%of organic solvents can be used to obtain good detection results.The detection limit of fluorescence?LOD?was 7.76×10^-8M;MTT experiments showed that the probe NIRHA has lower cytotoxicity and better biocompatibility.After incubating cells in probe solutions of different concentrations for 24 hours,the cell viability remained above 90%.Through cell imaging and biological experiments,it was found that the probe can successfully detect endogenous and exogenous cysteine in the cell,and the detection process is not disturbed by the cellular environment.The probe has good The in vivo imaging ability of mice can complete the detection of endogenous and exogenous cysteine in mice.2.Phenothiazine was used as a fluorophore,and a Knoevenagel-Doebner condensation reaction between indium sulfonate and indole sulfonate was used to design and synthesize a fluorescent probe PHTP with the ability to detect cyanate and cyanous sulfite at two wavelengths.During the use of this probe,HSO₃^-can be specifically detected in a neutral environment,resulting in a specific fluorescence signal change?450nm?without the interference of CN^-;it can be specific in alkaline environments The detection of CN^-,produces a change in the fluorescence signal at507nm,and HSO₃^-has no interference.Compared with existing probes,PHTP has the advantages of good water solubility,fast response,and low detection limit(cyanide,LOD=9.8×10^-8 M;bisulfite,LOD=3.0×10^-8 M),etc.The possible detection mechanism was inferred by NMR titration,high-resolution mass spectrometry experiments and Gaussian theoretical calculations.Through cell imaging experiments,it was found that the probe PHTP can be used for fluorescence development in HeLa cells,and has a good application prospect.3.Based on the previous work,a Knoevenagel-Doebner condensation reaction was used to design and synthesize fluorescent probes with three-wavelength differential detection capability for cyanide,cyanite,and hypochlorite starting from triphenylamine and indolesulfonate TIM.When detecting CN^-,HSO₃^-,and ClO^-,the probe can generate fluorescence signals with different wavelengths at 473nm,378nm,and 425nm,and the detection limits are 4.5×10^-88 M,4.3×10^-88 M,and 4.9,respectively.×10^-7 M.NMR titration,high-resolution mass spectrometry,and theoretical calculations explain the different mechanisms of the reaction between the three analytes and the probe.And through biological experiments,it was found that the probe can perform fluorescence imaging of CN^-,HSO₃^-and ClO^- in both HeLa cells and MDCK cells.