Fluorescent sensors for selective detection of thiols: expanding the intramolecular displacement based mechanism to new chromophores.
Biological thiols, including cysteine (Cys), homocystein (Hcy) and glutathione (GSH), play crucial roles in maintaining the appropriate redox status of biological systems. An abnormal level of biothiols is associated with different diseases, therefore, the discrimination between them is of great importance. Herein, we present two fluorescent sensors for selective detection of biothiols based on our recently reported intramolecular displacement mechanism. We expanded this mechanism to commercially available chromophores, 4-chloro-7-nitro-2,1,3-benzoxadiazole (NBD-Cl) and heptamethine cyanine dye IR-780. The sensors operate by undergoing displacement of chloride by thiolate. The amino groups of Cys/Hcy further replace the thiolate to form amino-substituted products, which exhibit dramatically different photophysical properties compared to sulfur-substituted products from the reaction with GSH. NBD-Cl is highly selective towards Cys/Hcy and exhibits significant fluorescence enhancement. IR-780 showed a variation in its fluorescence ratio towards Cys over other thiols. Both of the sensors can be used for live-cell imaging of Cys. The wide applicability of the mechanism may provide a powerful tool for developing novel fluorescent sensors for selective detection of biothiols.
Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China. qzyang@mail.ipc.ac.cn.
Li-Ya
LY
Niu
Hai-Rong
HR
Zheng
Yu-Zhe
YZ
Chen
Li-Zhu
LZ
Wu
Chen-Ho
CH
Tung
Qing-Zheng
QZ
Yang
D009327:4-Chloro-7-nitrobenzofurazan / Q000737:chemistry*; D002460:Cell Line; D003545:Cysteine / Q000032:analysis*; D005456:Fluorescent Dyes / Q000737:chemistry*; D005978:Glutathione / Q000032:analysis*; D006367:HeLa Cells; D006710:Homocysteine / Q000032:analysis*; D006801:Humans; D007211:Indoles / Q000737:chemistry*; D061848:Optical Imaging; D013050:Spectrometry, Fluorescence; D013438:Sulfhydryl Compounds / Q000032:analysis
C548458:2-(2-(2-chloro-3-((1,3-dihydro-3,3-dimethyl-1-propyl-2H-indol-2-ylidene)ethylidene)-1-cyclohexen-1-yl)ethenyl)-3,3-dimethyl-1-propylindolium; D005456:Fluorescent Dyes; D007211:Indoles; D013438:Sulfhydryl Compounds; D006710:Homocysteine; D009327:4-Chloro-7-nitrobenzofurazan; D005978:Glutathione; D003545:Cysteine