A highly specific and sensitive turn-on fluorescence probe for hypochlorite detection and its bioimaging applications

Development of high performance fluorescent chemosensors for the detection of ClO^- in vitro and in vivo is very desirable, because many human diseases are caused by ClO^-. In this paper, a highly selectivity and sensitive fluorescent probe, EDPC, based on 3-acetylcoumarin, was synthesized, which could respond to ClO^- and exhibit an "off-on" mode in Tris-HCl buffer (pH = 7.2, 10 mM, 50% C₂H₅OH) solutions. The detection limit of the EDPC probe for ClO^- was as low as 1.2 × 10^-8 M. Moreover, the high selectivity and high sensitivity of EDPC towards ClO^- are attributed to the oxidation reaction between the C-O of the coumarin lactone and the C[double bond, length as m-dash]C formed by aldol condensation and the mechanism was further verified using ESI-MS and DFT. Additionally, the concentrations of ClO^- in real water were also calculated using the EDPC probe and showed good recovery. Finally, the distribution of intracellular endogenous ClO^- was gained by confocal fluorescence microscopy in living HEK293T cells.