Turn-on Quinoline Probe for Selective Sensing of Hypochlorite in Live Cells

Abstract Hypochlorite is a significant reactive oxygen species (ROS) involved in various biological processes. Excessive levels of hypochlorite are linked to oxidative stress, which contributes to a number of diseases by altering the structure and function of biomacromolecules. Many existing probes for detecting hypochlorite have relatively high molecular weights and typically exhibit changes in emission wavelength upon interaction with the ROS. We have synthesized a quinoline-based probe, 5, which is not fluorescent on its own, but becomes fluorescent at 523 nm upon reaction with hypochlorite through an oxidative mechanism. This probe exhibits time sensitivity as low as 10 seconds outside of cells. Probe fluorescence is visible to the naked eye, with intensity increasing with ROS concentration. Furthermore, probe fluorescence is detected in cells in a concentration-dependent manner. Altogether, we describe the generation and use of a quinoline-based probe to detect hypochlorite ROS in live cells.