A FRET-based ratiometric fluorescence sensor for peroxynitrite detection and its application in living cells, zebrafish, and ultraviolet-induced mouse models imaging.

Peroxynitrite (ONOO) is not only a crucial ROS but also a significant RNS, and its abnormal expression level in vivo is substantially associated with the physiological and pathological outbreak of many diseases. Herein, a ratiometric fluorescence sensor QL-RH was successfully developed using the FRET strategy, in which quinoline and xanthene dye were adopted as the donor and acceptor for the fluorescence resonance energy transfer scaffold, respectively. When QL-RH reacts with ONOO by Bayer-Villiger oxidation reaction, and the fluorescence ratiometric response is triggered, the ratio value increases by 50-fold, and it has a good limit of detection (LOD) as low as 28.7 nM, which offered a chemical-specific sensitive molecular tool for the detection of ONOO, and the QL-RH of ratiometric characteristics were confirmed by Ultraviolet-Visible and fluorescence spectrophotometer. In addition, QL-RH was also successfully employed for the images of ONOO in live cells and zebrafish by LPS stimulation, which increased by ∼9-fold and 8-fold, respectively, and ∼8-fold in mice models irradiated under UV-light, which indicated that QL-RH could become a useful tool for monitoring the process of UV-induced skin aging.