Dual-functional colorimetric fluorescent probe for sequential Cu2+ and S2- detection in bio-imaging

It is highly indispensable to detect Cu2+ and S2- because of its vital role in living organisms and the environment. In this work, a novel on-off-on coumarin-based colorimetric fluorescent probe L for sequential recognition of Cu2+ and S2- was strategically designed and synthesized. It displays low detection limit measured to be 2 x 10(-8) M and 6 x 10(-8) M respectively for Cu2+ and S2- with high selectivity and excellent sensitivity. In addition, an appropriate broad pH of 4-10 allows probe L to be applied to the biological window, and MTT experiments show that probe L has negligible cytotoxicity, which demonstrate it can be employed to determine Cu2+ and S2- in A375 cells.