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-NO₂, enabling a highly selective detection of ONOO^-. Upon reaction with ONOO^-, the probe is converted into MeOTPE-NH₂, 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-NO₂ shows outstanding specificity for ONOO^- over other reactive oxygen and nitrogen species, minimizing potential interference. Owing to its low cytotoxicity, MeOTPE-NO₂ has been successfully applied for real-time imaging of ONOO^- in live cells and in a mouse model of inflammation.