title: A colorimetric and ratiometric fluorescent probe for selective detection and cellular imaging of glutathione.
abstract: A new colorimetric and ratiometric fluorescent probe 1 based on a chlorinated coumarinyl aldehyde was developed for selective detection and cellular imaging of glutathione (GSH) over cysteine (Cys) and homocysteine (Hcy). Probe 1 exhibits a dramatic colorimetric and ratiometric fluorescence responses toward biothiols Cys, Hcy and GSH with high selectivity over other amino acids. Cys (or Hcy) induces a tandem SNAr-rearrangement reaction to form the corresponding amino-coumarins (2a or 2b), which result in about 75 nm and 35 nm blue-shifts in absorption and emission, respectively. By comparison, the thio-coumarin (3') derived from the SNAr reaction with GSH, which does not occur rearrangement because of steric hindrance, undergoes an intramolecular aldimine condensation lead to a cyclic iminium cation (3) with 47 nm and 39 nm red-shifts in absorption and emission, respectively. The significantly difference of photophysical properties enable excellent selectivity towards GSH over Cys and Hcy. Further application to cellular imaging indicates that the probe has appreciable cell permeability and is highly responsive to the changes of GSH level. As a result, it is applicable to monitor GSH level in living cells.
authors.affiliation: Key Laboratory of Natural Resources of Changbai Mountain & Functional Molecules of the Ministry of Education, Department of Chemistry, Yanbian University, Yanji 133002, PR China.
authors.forename: Chang
authors.initials: C
authors.lastname: Xu
authors.affiliation: Department of Forensic Chemistry, National Police University of China, Shenyang 110854, PR China.
authors.forename: Hongda
authors.initials: H
authors.lastname: Li
authors.affiliation: Key Laboratory of Natural Resources of Changbai Mountain & Functional Molecules of the Ministry of Education, Department of Chemistry, Yanbian University, Yanji 133002, PR China. Electronic address: zqcong@ybu.edu.cn.
authors.forename: Bingzhu
authors.initials: B
authors.lastname: Yin
mesh_terms: D003124:Colorimetry; D003374:Coumarins / Q000737:chemistry*; D003545:Cysteine / Q000032:analysis; D005456:Fluorescent Dyes / Q000737:chemistry*; D005978:Glutathione / Q000032:analysis*; D006367:HeLa Cells; D006710:Homocysteine / Q000032:analysis; D006801:Humans; D008856:Microscopy, Fluorescence; D061848:Optical Imaging; D013050:Spectrometry, Fluorescence
chemical_list: D003374:Coumarins; D005456:Fluorescent Dyes; D006710:Homocysteine; C030123:coumarin; D005978:Glutathione; D003545:Cysteine
keywords: Cell imaging; Cysteine; Glutathione detection; Homocysteine; Ratiometric fluorescent probe; chlorinated coumarinyl aldehyde