A fast-response and highly selective near-infrared fluorescent probe for imaging peroxynitrite in living cells and...

Peroxynitrite (ONOO^-) is a crucial reactive oxygen species (ROS) that participates in a variety of physiological and pathological events in living organisms. Fluorescent probes have emerged as powerful tools for detecting ONOO^-. However, many existing probes still suffer from inherent drawbacks, including short emission wavelengths, slow response kinetics, and small Stokes shifts, severely limiting their utility for in vivo ONOO^- imaging. Herein, we report the design and development of DCMS, a new near-infrared (NIR) fluorescent probe capable of rapid and selective detection of ONOO^-.The probe was constructed by combining a dicyanomethylene-4H-pyran derivative as the NIR fluorophore and a phenylthiocarbonate unit as the ONOO^--responsive recognition motif. Upon treatment with ONOO^-, the thiocarbonate group underwent a specific oxidative cleavage, releasing the parent fluorophore and triggering a remarkable NIR fluorescence signal. DCMS showed high sensitivity, excellent selectivity, and rapid response kinetics toward ONOO^-. In addition, DCMS featured a large Stokes shift (130 nm), good photostability, and negligible cytotoxicity. Leveraging its favorable NIR emission properties, DCMS was successfully applied for real-time imaging of ONOO^- in living cells and mice. Collectively, these results suggest that DCMS holds great promise as a valuable tool for ONOO^- detection in biosystems and for the in-depth investigation of ONOO^--related physiological and pathological mechanisms.