An ɑ-ketoamide-based fluorescent probe via aggregation induced emission for ONOO detection in vivo.

Peroxynitrite (ONOO) plays a pivotal dual role in the inflammatory process. As a signaling molecule, it modulates the immune response, while its excessive production leads to oxidative stress and cellular damage, thereby exacerbating inflammation. Accurate detection of ONOO dynamics in inflammatory process is crucial for elucidating its pathological roles and developing targeted therapeutic strategies. In this study, we report a novel α-ketoamide-based fluorescent probe, MeOTPE-NO, enabling a highly selective detection of ONOO. Upon reaction with ONOO, the probe is converted into MeOTPE-NH, featuring with aggregation-induced emission (AIE) property, which emits a strong fluorescence at 505 nm. This probe exhibits high specificity, sensitivity, and rapid fluorescence response, along with excellent pH stability across a broad range. Furthermore, MeOTPE-NO shows outstanding specificity for ONOO over other reactive oxygen and nitrogen species, minimizing potential interference. Owing to its low cytotoxicity, MeOTPE-NO has been successfully applied for real-time imaging of ONOO in live cells and in a mouse model of inflammation.