Recognition of HClO in Live Cells with Separate Signals Using a Ratiometric Fluorescent Sensor with Fast Response

Hypochlorous acid (HClO), one of the reactive oxygen species (ROS), is a key microbicidal agent which is used for natural defense; however, it is also involved in several human diseases. Although several efforts have been made to develop HClO-selective fluorescent sensors, most of them display delayed response time and the ratiometric sensors are rare. In the current work, we used a 3-pyrrole BODIPY dye as a new ratiometric fluorescent sensor (<b>BRClO</b>) for HClO. <b>BRClO</b> exhibited a 177-fold fluorescence ratio (<i>F</i>_{505 nm}/<i>F</i>_{585 nm}) enhancement in the presence of HClO over other ROS with fast response time (completed within 1 s). Confocal fluorescence imaging with <b>BRClO</b> showed separated signals in the presence of exogenous HClO in live cells. In addition, <b>BRClO</b> could be easily prepared as HClO test strips to detect HClO in aqueous solution and natural tap water