Coumarin-Based Reversible Fluorescent Probe for Selective Detection of Cu in Living Cells.

Copper ion plays an important role in many biological processes in human body. HS is considered as the third gasses transmitter after carbon monoxide and nitric oxide. Here a novel ICT-based fluorescent ON-OFF-ON probe for Cu and HS detection was developed. Selectivity and sensitivity of probe was confirmed in aqueous Tris-HCl buffer (10 mM, pH 7.4, containing 90% acetonitrile). Probe DF-CU shows high selectivity over other analytes. The degree of fluorescence quenching is linearly associated with the concentration of Cu (R = 0.9919). The limit of detection (LOD, calculated according to the 3σ/slope) for Cu was 6.4 μM. Probe can work in almost all pH. The probe shows a very fast response to Cu (within 10 s). Its response to copper ion could be reversed by HS. The complex of probe with Cu could be used for HS detection. Furthermore, this ON-OFF-ON fluorescent probe successfully applied in the living cells for the detection of Cu and HS.