A novel turn-on fluorescent probe based on trimethyl lock with acrylate recognition moiety and latent fluorophore of 4-amino-7-nitrobenz-2-oxa-1,3-diazole (NBD-NH2) for the detection of glutathione has been developed. The probe can selectively and sensitively detect glutathione in solution, and the limit of detection was calculated to be 26 nM. Furthermore, the probe has been successfully used to detect GSH in living cells. The interesting preference of GSH was attributed to the steric repulsion of trimethyl which retarded Cys, Hcy to reach Burgi-Dunitz angle and allowed more flexible side cha...