A novel near-infrared fluorescent probe for peroxynitrite imaging in cellular and organ injury

Peroxynitrite (ONOO^-), a crucial reactive oxygen/nitrogen species, plays a significant role in various physiological and pathological processes. However, its excessive accumulation can lead to severe diseases, necessitating effective detection methods. Herein, we report a novel near-infrared fluorescent probe (DCI-ONOO) for sensitive and selective ONOO^- detection, utilizing dicyanoisophorone as the fluorophore and a diphenylphosphinic group as the recognition moiety. The probe exhibits excellent photophysical properties, including a large Stokes shift (208 nm), good photostability, and a low detection limit (39.8 nM). Upon interaction with ONOO^-, DCI-ONOO demonstrates a significant fluorescence enhancement at 670 nm through an intramolecular charge transfer mechanism. The probe shows remarkable selectivity toward ONOO^- over other reactive oxygen/nitrogen species and maintains stability under various pH conditions. Furthermore, DCI-ONOO displays minimal cytotoxicity and effective membrane permeability, enabling successful imaging of both exogenous and endogenous ONOO^- in living cells. Notably, the probe effectively monitored ONOO^- fluctuations in acetaminophen-induced liver and kidney injury models, revealing previously unreported ONOO^- generation patterns in systemic metabolic organs. These findings demonstrate DCI-ONOO potential as a valuable tool for studying ONOO^--related biological processes and drug-induced organ damage.