Construction of a Mitochondria‐Endoplasmic Reticulum Dual‐Targeted Red‐Emitting Fluorescent Probe for Imaging Peroxynitrite in Living Cells and Zebrafish

Peroxynitrite (ONOO- ) is one of the important reactive oxygen species, which plays a vital role in the physiological process of intracellular redox balance. Revealing the biological functions of ONOO- will contribute to further understanding of the oxidative process of organisms. In this work, we designed and synthesized a novel red-emitting fluorescent probe MCSA for the detection of ONOO- , which could rapidly respond to ONOO- within 250 s and exhibited high sensitivity to ONOO- with a low detection limit of 78 nM. Co-localization experiments demonstrated MCSA had the ability to localize into the mitochondria and endoplasmic reticulum. What's more, MCSA enabled monitoring ONOO- level changes during tunicamycin-induced endoplasmic reticulum stress. We have also successfully achieved the visual detection of exogenous and endogenous ONOO- in living cells and zebrafish. This work presented a chemical tool for imaging ONOO- in vitro and in vivo.