A novel highly selective near-infrared and naked-eye fluorescence probe for imaging peroxynitrite

Peroxynitrite (ONOO−) is closely related to various physiological and pathological processes. Real-time, selective, and sensitive detection of ONOO− is of great importance. Based on the intramolecular charge transfer (ICT) mechanism, a novel near-infrared (NIR) and naked-eye fluorescence probe DCIPP was developed with “turn-on” fluorescence properties for monitoring ONOO− in living cells. The probe DCIPP is composed of a dicyanoisophorone electron-accepting scaffold and a reactive electron-drawing diphenyl phosphoryl group for imaging ONOO−. Upon addition of ONOO−, the fluorescence intensity of DCIPP is enhanced obviously at 665 nm in emission spectra, and the colour of DCIPP solution changes from pale yellow to purple at the same time. Based on the nucleophilic propensity of ONOO−, this probe displays highly selective detection of ONOO− over other various bioactive molecules and could quantitatively and sensitively detect ONOO− with a low limit of detection (LOD) of 33 nM by the fluorescence method and 0.29 μM by the UV method. Moreover, DCIPP was successfully applied to the fluorescence imaging of ONOO− in living cells and zebrafish with good cell-membrane permeability and low cytotoxicity.