Synthesis And Performance Analysis Of Fluorescent Probes For Detecting Viscosity And Bioactive Species

Small molecule fluorescent probes have many advantages,such as simple synthesis,multiple recognition groups,low biotoxicity,good cell penetration and so on.They are often used in combination with fluorescence confocal imaging technology for detecting biological microenvironment factors such as biological active substances,anion,viscosity and so on.However,due to the high reactivity and short lifetime of active species,it also brings challenges to the detection.Therefore,fluorescent probes with high sensitivity and selectivity are designed and synthesized to improve the stability,spectral diversity and organelle localization ability of the probes.At present,there are few reports on rhodamine viscosity probes.Therefore,the design and synthesis of rhodamine viscosity fluorescent probes with superior performance has become the mainstream of development.In order to overcome the above problems,this paper mainly carries out the following work:（1）Quinone was fused into rhodamine structure to construct fluorescent dye RQF.RQF structure has the following advantages:（1）Due to the fusion of quinone into the structure,theπ-conjugated system was increased and the emission wavelength was extended to 660 nm.（2）The dye RQF not only retained the spiral structure,but also introduced highly electronegative fluorine atoms to increase the reaction sites.（3）RQF can be used as a high selective mitochondrial viscosity fluorescent probe without structural modification.（2）Fluorescent probes Bt₂Bp and Nt Bp were synthesized by introducing electron withdrawing groups benzothiazole and naphthothiazole with dithiophene as connecting arm.The application of two probes in viscosity and anion recognition was studied systematically.Probes Bt₂Bp and Nt Bp used C=C/C=N double bonds as reaction sites to realize highly selective recognition of HSO₃^-/SO₃^2-.The detection limit of the probes were as low as 0.61 n M and 2.38 n M,and the response time was<10 s.Moreover,fluorescence imaging of HSO₃^-/SO₃^2-in living cells can be realized.Make the use of the structural characteristics of Bt₂Bp,the viscosity in living cells can also be detected.（3）The electron withdrawing group containing-CN was connected with the electron donor group to form a DCM symmetrical fluorescent probe Xan CN.The emission wavelength of the light fluorescent probe Xan CN was 750 nm in the near infrared region.Meanwhile,HOCl fluorescence ratio imaging in lysozyme was realized by utilizing conjugate double bond of HOCl oxidation probe Xan CN to achieve high speed response to HOCl.