A phosphinate-based near-infrared fluorescence probe for imaging the superoxide radical anion in vitro and in vivo.

A novel near-infrared (NIR), turn-on fluorescence probe CyR containing a phosphinate group as a recognizing moiety for the selective detection of O-2(center dot-) with a low limit of detection (LOD, 9.9 nM) was developed. CyR has good cell-membrane permeability, intracellular stability, and low cytotoxicity. In addition, we successfully applied the CyR to visualize O-2(center dot-) in live zebrafish, mouse and, for the first time, in mouse liver.