文摘
Peroxynitrite (OONO–) is profoundly implicated in health and disease. The physiological and pathological outcome of OONO– is related to its local concentration, and hence, a reliable OONO– assay is highly desired. We have developed a FRET-based small-molecule fluorescent probe (PNCy3Cy5), harnessing the differential reactivity of Cy3 and Cy5 toward OONO– by fine-tuning. It exhibits high detection sensitivity and yields a ratiometric fluorescent signal. We have exemplified that it can be applied in semiquantitative determination of OONO– in living cells. Notably, it specifically localizes in mitochondria, where endogenous OONO– is predominantly generated. Thus, PNCy3Cy5 is a promising molecular tool for peroxynitrite biology.