A simple ratiometric fluorescent sensor selectively compatible of different combinations of characteristic groups for identification of glutathione, cysteine and homocysteine

Simultaneous detection of biothiols would be helpful for understanding their biological functions and pathological study of related diseases. The structural similarities of biothiols present a great challenge to achieve their selective detection. Herein, we report a simple acrylate-substituted fluorescent sensor BTHA with one recognition site and an assisted neighboring hydroxy group for this purpose. BTHA exhibited an emission band at 507 nm with a 147 nm Stokes shift. Upon addition of glutathione (GSH) or cysteine (Cys), deacrylate product was obtained and new fluorescent band at 459 nm occurred. The addition reaction product with decreased fluorescence was achieved as BTHA was treated with homocysteine (Hcy). BTHA acts with the mercapto group of Cys, the mercapto and amino group of Hcy, and the mercapto and carboxyl group of GSH, respectively. Correspondingly, different ratiometric fluorescence changes (I459/I507) with these biothiols was produced. Using the two-dimensional map with two channel signals, BTHA can simultaneous distinguish GSH, Cys and Hcy. The sensor BTHA can also be used for exogenous and endogenous GSH imaging with ratiometric fluorescence response in live cells.