A fast-response, highly specific fluorescent probe for the detection of picomolar hypochlorous acid and its bioimaging applications

Highly specific and ultrasensitive fluorescent probes for tracking the intracellular native hypochlorous acid (HOCl) levels are urgently needed owing to its important molecular functions in the biological systems. In this contribution, a simple thiocarbamate-caged 7-hydroxycoumarin (TCHC) was developed as fluorescent probe for monitoring HOCl in live cells. Probe TCHC exhibited preeminent specificity towards HOCl over other various bioactive substances. Importantly, probe TCHC could sensitively detect HOCl in the range of 0-175 pM with the detection limit of 17 pM, which was attributed to the multiple fluorescence sensing mechanisms including photo-induced electron transfer (PET), intramolecular charge transfer (ICT), and the chlorination. Furthermore, probe TCHC displayed an instant response towards HOCl (<3 s), and thus the real-time detection of HOCl could be achieved. Finally, probe TCHC was successfully applied to monitor native HOCl and the fluctuations of endogenous HOCl levels in live cells. (C) 2018 Elsevier B.V. All rights reserved.