A mitochondria -specific fluorescent probe based on triazolopyridine formation for visualizing endogenous hypochlorous acid in living cells and zebrafish

Biological hypochlorous acid (HOCl), a reactive oxygen species (ROS) with high activity, plays a crucial role in normal biochemical functions and abnormal pathological processes related to oxidative stress. However, “eco-friendly” tools to unambiguously monitor subtle changes of mitochondrial HOCl in vivo are limited. Herein, a novel mitochondria-specific and “eco-friendly” fluorescent probe (NM1) using triphenylphosphonium as the targeting group is designed for the detection of biological HOCl by a HOCl-promoted triazolopyridine formation strategy. This HOCl-promoted triazolopyridine formation reaction is fast and does not release additional substances except H2O. Therefore, NM1 is not only an “eco-friendly” HOCl probe, but also can target mitochondria to monitor biological HOCl in situ and in real time. Better still, our probe NM1 is capable to image endogenous HOCl in living HepG2 cells and zebrafish. © 2020 Elsevier B.V.