Activatable red emitting fluorescent probe for rapid and sensitive detection of intracellular peroxynitrite

Peroxynitrite (ONOO^-), a highly reactive oxygen species generated by the reaction of nitric oxide and superoxide radical anion, is involved in numerous physiological and pathological processes in the human body. To identify important pathogenic mechanisms, it is crucial to develop a reliable tool for detecting peroxynitrite in living systems. In the present study, a new difluoroboron β-diketonate-based fluorescent probe for detecting exogenous and endogenous peroxynitrite in living systems was designed. The red emitting fluorophore can be synthesized in a simple three-step procedure. This probe reacts quickly and selectively with peroxynitrite and its detection limit is determined to be as low as 19.8 nM. It allows for clear imaging of peroxynitrite in RAW 264.7 cells and was successfully applied to visualize changes of intracellular peroxynitrite induced by reactive oxygen species inhibitors. This designed probe is an effective tool for investigating the physiological and pathological role of peroxynitrite in living cells.