A hypochlorous acid turn-on fluorescent probe based on HOCl-promoted oxime oxidation and its application in cell imaging

A coumarin-based fluorometric probe, HS1, has been successfully developed for highly sensitive and selective detection of hypochlorous acid (HOCl). The probe is based on the specific HOCl-promoted oxidation of oxime. The reaction is accompanied by a 7-fold increase in the fluorescent quantum yield (from 0.03 to 0.21). The fluorescence intensity of the reaction between HOCl and HS1 shows a good linearity in the HOCl concentration range of 1–20 μM and a low detection limit of 25 nM (S/N = 3). In addition, confocal fluorescence microscopy imaging using RAW264.7 macrophages demonstrates that the HS1 probe could be an efficient fluorescent probe for HOCl in living cells.