Recognition Biothiol By Fluorphore Modification Of Ferrocene Based On Disulfide Bond Cleavage

The disulfide bond?-S-S-?is a relatively stable covalent bond with dynamic reversible properties.It can be cleavaged to form a thiol-containing compound in the presence of biothiol.Ferrocene?Fc?is a compound with unique"sandwich"structure.It has excellent redox and electron-rich properties and can be used as a quencher for the construction of PET fluorescent probe.The endogenous concentrations of thiols?GSH?Cys?Hcy?suggest that their abnormal levels correlate with many diseases.Therefore,in this parper,the disulfide bond is used as a biothiol specific recognition site,and ferrocene is used as a fluorescence quencher,to design and synthesize a series of biothiol fluorescent probe?Py-Fc,Py-N-Fc,NapH-Fc,TPEPy-Fc?based on PET mechanism.1?The probes Py-Fc and Py-N-Fc are synthesized at different distances between the pyrene fluoropHore and the ferrocene quencher by simple synthesis method.By fluorescence emission spectroscopy,we found that the PET quenching effect of the probe Py-Fc was better than Py-N-Fc.And the probes can selective detect of GSH,Cys and Hcy.In the presence of GSH,the probe can completed in 2 hours,and a large emission enhancement is observed over a wide pH range of 7.0¹1.0.The detection limit of probe Py-Fc,Py-N-Fc for GSH were determined to be 5.11×10^-77 M?8.83×10^-77 M,respectively.2?With 4-bromo-1,8-naphthalic anhydride as the starting material,a ferrocene appended dyad NapH-Fc with green emission was prepared.By fluorescence emission spectroscopy,the probe can identify GSH,Cys and Hcy with a large fluorescence enhancement in DMSO-PBS?2:8 v/v,0.01 M,pH=7.4?buffer system.The detection limits of probe toward these three targets are 1.34×10^-88 M,2.47×10^-7M and 1.13×10^-8M,respectively.The probe can completed in 45 min over a wide pH range of 7.0¹1.0.The probe has a low cytotoxicity and a cell viability of 75%in the range of 0²5?M.By Confocal fluorescence images of the biothiol in HeLa cells,the intracellular fluorescence intensity increases with the incubation time,and can accurately image the biothiol in HeLa cells.3?A near-infrared fluorescence emission probe TPEPy-Fc was obtained by coupling reaction with 4-vinylpyridine and ferrocene.By fluorescence emission spectroscopy,the probe TPEPy-Fc can identify GSH,Cys and Hcy well in 0.01 M pH=7.4 DMSO-PBS?1:199;v/v?buffer system.The detection limits are 7.69×10^-77 M,4.68×10^-77 M,5.98×10^-7M,respectively.The probe can completed in 80 min,and a large emission enhancement is observed over a wide pH range of 7.0⁹.0.The probe has a low cytotoxicity and good biocompatibility in the range of 0⁶0?M,and the cell survival rate is over 90%.The probe can accurate imaging of biothiol in CT-26cells.