Mito-Specific Ratiometric Terbium(III)-Complex-Based Luminescent Probe for Accurate Detection of Endogenous Peroxynitrite by Time-Resolved Luminescence Assay.

The level of peroxynitrite (ONOO) is closely related to the pathogenesis of a series of diseases. Hence, the accurate sensing of ONOO is very important for a better understanding of its biological functions. Here, a time-resolved ratiometric nanoprobe (TD-DC) composed of an energy donor unit (Tb(DPA), where DPA signifies a dipicolinate dianion ligand) and an energy receptor unit (DC) was designed. The response of TD-DC toward ONOO in vitro was assessed by luminescence intensity and lifetime. The results demonstrated that TD-DC could precisely (39 nM) detect ONOO with high selectivity and efficiency (29 s). TD-DC was further successfully employed in sensing endogenous ONOO in A-375 cells. Moreover, it could specifically localize in the mitochondrion, where endogenous ONOO is mainly generated. The above results revealed that TD-DC is efficient and useful for real-time detection of ONOO at subcellular levels.