Development of FRET-based Ratiometric Fluorescent Cu2+ Chemodosimeters and the Applications for Living Cell Imaging

Coumarin-rhodamine-based compounds 1a,b were rationally designed and synthesized as novel FRET ratiometric fluorescent chemodosimeters. Ratiometric chemodosimeters 1a,b exhibit several favorable features, including a large variation in the emission ratio, well-resolved emission peaks, high sensitivity, high selectivity, low cytotoxicity, and good cell membrane permeability. Importantly, these excellent attributes enable us to demonstrate ratiometric imaging of Cu(2+) in living cells by using these novel ratiometric fluorescent chemodosimeters.