TCF-imidazo[1,5-α]pyridine: A potential robust ratiometric fluorescent probe for glutathione detection with high selectivity

A novel fluorescent probe, TCF-IPY, has been designed and developed for highly selective and ratiometric detection of GSH based on the extend of the pi-conjugation system of imidazo[1,5-alpha]pyridine IPY-CHO. Upon addition of GSH, TCF-IPY displayed remarkable fluorescence variations (approximate 949-fold ratio changes) from 603 nm to 475 nm, thereby enabling GSH detection in a fine ratiometric manner. Moreover, TCF-IPY exhibited excellent selectivity toward GSH over other biologically related species including Cys and Hcy. The huge blue shifts both in absorption (259 nm) and emission spectra (128 nm), low cytotoxicity, high sensitivity (97 nM) and rapid response (240 s) of TCF-IPY make it a robust molecular tool for endogenous GSH investigation. Furthermore, TCF-IPY was also successfully used for ratiometric imaging of endogenous GSH in living MCF-7 cells and zebrafish.