HKOH-1: A Highly Sensitive and Selective Fluorescent Probe for Detecting Endogenous Hydroxyl Radicals in Living Cells

The hydroxyl radical (^. OH), one of the most reactive and deleterious reactive oxygen species (ROS), has been suggested to play an essential role in many physiological and pathological scenarios. However, a reliable and robust method to detect endogenous ^. OH is currently lacking owing to its extremely high reactivity and short lifetime. Herein we report a fluorescent probe HKOH-1 with superior in vitro selectivity and sensitivity towards ^. OH. With this probe, we have calibrated and quantified the scavenging capacities of a wide range of reported ^. OH scavengers. Furthermore, HKOH-1r, which was designed for better cellular uptake and retention, has performed robustly in detection of endogenous ^. OH generation by both confocal imaging and flow cytometry. Furthermore, this probe has been applied to monitor ^. OH generation in HeLa cells in response to UV light irradiation. Therefore, HKOH-1 could be used for elucidating ^. OH related biological functions.