Novel Isophorone Fluorescent Probe for Ratiometric Peroxynitrite Imaging in Vivo

As one of the most essential active nitrogen species, the abnormal metabolism of ONOO- in biological systems is considered to be associated with multiple diseases. Therefore, real-time in situ monitoring of organisms' ONOO- levels is highly significant for the in-depth investigation of their molecular mechanisms and early diagnosis of related diseases. Here, we reported a fluorescent probe, IPPN3, based on a novel trifluoroacetamide-based strategy, enabling sensitive and rapid detection of ONOO- in aqueous solutions. Leveraging the specific oxidative hydrolysis reaction of ONOO- towards trifluoroacetamide moiety, the probe exhibits a substantial ratiometric fluorescence response to ONOO- with notable advantages including high selectivity, low detection limit (31.6 nM) and instantaneous response (less than 10 seconds). Furthermore, additional live-cell imaging results demonstrate the capability of IPPN3 for real-time exogenous and endogenous ONOO- fluorescence imaging in both live HeLa cells and zebrafish. The successful development of the IPPN3 may offer a new tool for tracking ONOO- levels in biological organisms in real time and exploring their biological functions.