A new coumarin-based fluorescent probe for selective recognition of Cu2+ and S2− in aqueous solution and living cells

A new coumarin-based fluorescent probe CMOH was easily synthesized for detection of Cu2+ and S2− in aqueous media and living cells. CMOH displayed high sensitivity (detection limit = 3.2 nM) and selectivity to Cu2+ with a non-fluorescence complex CMOH-Cu2+ formation via a 1:1 binding mode. According to displacement approach, the fluorescence of CMOH-Cu2+ was recovered in the presence of S2− and acted as a sensitive sensor with a low detection limit of 11.4 nM. This ‘‘on-off-on’’ process can be accomplished within 1 min and repeated at least 5 times. What's more, CMOH exhibited good permeability, low cytotoxicity and can be used as a suitable tool to detect changes of Cu2+ and S2− in biosystem.