Furan-modulated ClO- probe with typical turn-on fluorescence response, high signal-to-noise ratio and reactivity for applications in food samples, test strips, live cells and zebrafish.

As a reactive oxygen species (ROS) and antibacterial agent, hypochlorite (ClO-) is crucial in both food processing and life activities, and ClO- fluorescent probes have been widely proposed in recent years. However, research on further improving their sensing performance is still not comprehensive enough. In this work, by introducing benzene and furan groups with different electronegativity, three aggregation-induced emission (AIE) based ClO- fluorescent probes with CN bond as the reaction site were rationally prepared. After comparative analysis, it was found the furan group with stronger electron-donating ability can completely eliminate the fluorescence of Probe C, and after the addition of ClO-, it showed a typical turn-on fluorescence response with a signal-to-noise ratio (S/N) of up to 58.26-fold. Meanwhile, combined with its low background fluorescence, Probe C exhibited better detection sensitivity, and the detection limit (LOD) was as low as 0.16 μM. Moreover, with the assistance of electron-withdrawing diaminomaleonitrile (DAMN), Probe C also demonstrated higher reactivity toward ClO- due to the increased electron cloud density around the reaction site, and the reaction equilibrium can be achieved within 4 min. Eventually, Probe C with high specificity and photostability was successfully applied to the accurate determination of ClO- in food samples, and demonstrated satisfactory performance in naked-eye recognition using test strips, as well as live cell and zebrafish imaging.