Development of a novel highly specific fluorescent probe for detecting HOCl in living cells and zebrafish, as well as real water samples

• A new chromene derivative probe for HOCl was designed and synthesized. • The probe shows a rapid and considerable fluorescence response with low detection limit. • The probe was utilized to visualize HOCl in cells, zebrafish and real water samples. Hypochlorous acid (HOCl), a member of reactive oxygen species (ROS), plays an important role in living systems. Highly sensitive probes for detection of hypochlorous acid are in great demand. A novel chromene derivative fluorescent probe was constructed for determining hypochlorous acid. When HOCl was absent, the probe itself exhibited strong fluorescence intensity, while the fluorescence was quenched with the presence of HOCl. The fluorescent probe exhibited high selectivity and sensitivity for HOCl in a linear response range of 0 -15 μM with a low detection limit of 0.12 μM. The probe has been successfully applied for the confocal imaging of HOCl in the RAW 264.7 cells and zebrafish with low cell toxicity. It also was used to detect HOCl in tap water and lake water.