A sensitive fluorescent probe for cysteine and Cu2+ based on 1,8-naphthalimide derivatives and its application in living cells imaging

A new 1,8-naphthalimide derivative (NAD) was synthesized and employed as a highly sensitive and selective probe for the detection of cysteine (Cys) and Cu 2+ . The terminal olefin of NAD could react with Cys and resulting in fluorescence quenching , with the adding of Cu 2+ , the schiff base unit of NAD could coordinate with Cu 2+ and lead to a highly selective fluorescence “turn-on” response. The detection limits reached as low as 25 nM for Cys and 11 nM for Cu 2+ . In addition, the NAD probe can be further applied to cells imaging owing to its photostability and low cytotoxicity.