Rationally designed meso-benzimidazole-pyronin with emission wavelength beyond 700 nm enabling in vivo visualization of acute-liver-injury-induced peroxynitrite

Fluorescent dyes with fluorescence emission above 700 nm are favorable for bio-imaging due to the higher tissue transparency and lower background fluorescence. In this study, we present a meso-benzimidazole-pyronin platform (SiBMs) with fluorescence emission maxima above 700 nm, which possess good cell permeability, photostability, and lysosomal localization. The great photophysical properties of the SiBMs encouraged us to further exploit their application toward bio-imaging. We synthesized the reduced 'dihydro' derivative HSiBM3 for sensing ONOO-, with high selectivity and sensitivity and a fast fluorescence "off-on" response (within 2 s). Then, we confirmed the potential of HSiBM3 for visualizing exogenous and endogenous ONOO- in cells and mice. More importantly, HSiBM3 was successfully employed for visualizing acute-liver-injury-induced peroxynitrite. (c) 2023 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.