A mitochondria-targeted far red fluorescent probe for ratiometric imaging of endogenous peroxynitrite

Peroxynitrite (ONOO⁻), one reactive oxygen species, is related to various physiological and pathological activities. However, detailed mechanisms of peroxynitrite in biological systems are not thoroughly understood. Thus, the accurate detection of peroxynitrite with rapid response is essential for revealing its functions. Herein, we present a far red fluorescent probe Mito-WQPhOH to ratiometric monitor ONOO⁻ in vitro and living cells. Mito-WQPhOH showed the merits of fast response (<20 s), outstanding selectivity and excellent sensitivity towards ONOO⁻. Importantly, owing to the good water-solubility, great biocompatibility and excellent mitochondria targeting of Mito-WQPhOH, it was used for ratiometric imaging endogenous ONOO⁻ in living macrophages. Therefore, Mito-WQPhOH could act as a potential tool to reveal mechanisms of ONOO⁻ in biological systems.