Fast-Response Fluorogenic Probe for Visualizing Hypochlorite in Living Cells and in Zebrafish

A fast-response fluorogenic probe—compound D1—for monitoring hypochlorite (ClO ⁻ ), based on specific ClO ⁻ cleavage of a C=N bond and producing results observable to the naked eye, has been developed. The response of the probe to ClO ⁻ increases linearly, and the fluorescence intensity was heightened by a factor of about 25. D1 responses to ClO ⁻ , with high selectivity and sensitivity, were observable by naked eye within 10 s. D1 can not only detect levels of hypochlorite in vitro, such as in urine, but is also capable of monitoring hypochlorite content under extremely cold conditions, as low as −78 °C. Meanwhile, its good biocompatibility permitted the use of D1 to detect intracellular ClO ⁻ by confocal microscopy. Moreover, D1 was successfully applied to monitor exogenous and endogenous ClO ⁻ in zebrafish through fluorescence imaging.