Near-infrared fluorescent probe with rapid response and large Stokes shift for imaging peroxynitrite in living cells, zebrafish and mice

Detection and imaging of peroxynitrite (ONOO−) in living systems has attracted considerable attention in recent years due to its biological significance. In this paper, a new highly selective and sensitive near-infrared (NIR) fluorescent turn-on probe for ONOO− was developed. This probe uses a dicyanoisophorone-based fluorescent dye as the fluorophore and α-ketoamide as the reaction site. In the presence of ONOO−, the probe exhibits notable fluorescence enhancement at 660 nm with rapid response (<2 s), large Stokes shift (200 nm), and a low detection limit (81 nM). In addition, MTT assays indicated that this probe is of low cytotoxicity in cells, and bioimaging experiments demonstrated that the probe could be applied for imaging of ONOO− in living cells, zebrafish and mice with good imaging performance.