Fluorescent chemodosimeter for Cys/Hcy with a large absorption shift and imaging in living cells

A novel molecule T1 with efficient intramolecular charge transfer was designed as a fluorescent chemodosimeter for cysteine (Cys) and homocysteine (Hcy). Upon addition of Cys/Hcy, T1 exhibited greatly enhanced fluorescence intensity as well as a large absorption peak shift (70 nm), and can be used for bioimaging of Cys/Hcy in living cells and detection in human plasma by visual color change. The detection mechanism was proved by (1)H NMR, mass spectrometry analysis and Gaussian calculations.