LAUSR

Peroxynitrite (ONOO−) plays an essential role in numerous physiological and pathological processes owing to its strong oxidation and nitrification. Many studies have shown that ONOO− abnormalities are associated with inflammatory diseases, even cancer, such as arthritis, hepatitis, pneumonia, and breast cancer. Thus, developing a trustworthy technology to monitor ONOO− levels is critical in inflammatory or cancer illnesses. Herein, an ultrafast near-infrared (NIR) fluorescent probe (Cy–OH–ONOO) is proposed to detect ONOO− within 30 s. The probe's borate moiety is oxidized and separated from Cy–OH–ONOO, releasing a NIR fluorescence signal after interacting with ONOO− under physiological circumstances. In addition, the probe displays good selectivity and sensitivity towards ONOO− compared to other related biological species. Moreover, it is applied to the image and detects the level fluctuation of ONOO− in living cells and breast cancer mice based on excellent features with high biocompatibility and low toxicity of the developed probe. Therefore, Cy–OH–ONOO could serve as a powerful imaging tool to understand the correlation of ONOO− with inflammatory or breast cancer pathophysiological processes and to assess ONOO− levels in cellular oxidative stress.