Dynamic and Reversible Fluorescence Imaging of Superoxide Anion Fluctuations in Live Cells and in Vivo

Overgeneration of reactive oxygen species (ROS) is closely associated with cellular damage and diseases. As superoxide anion (O₂^•–) is the precursor of other ROS, exploring O₂^•– fluctuations in cells and in vivo is of great significance. To address this critical need, we have developed a novel reversible fluorescent probe with one-photon and two-photon fluorescence properties, which is well suited for monitoring O₂^•– fluxes selectively and dynamically. Imaging results substantiate dynamic and reversible fluorescence responses of this probe to intracellular O₂^•– under apoptotic stimuli. Moreover, this probe can conveniently visualize changes in O₂^•– concentration during reperfusion injury in hepatocytes, zebrafish, and mice, by means of one-photon or two-photon imaging according to depths of various samples. The present study provides a powerful fluorescent imaging tool for dynamic tracking of O₂^•– in live cells and in vivo.