Versatile Fluorescent Probes for Imaging the Superoxide Anion in Living Cells and In Vivo

Abstract The superoxide anion (O 2 .− ) is widely engaged in the regulation of cell functions and is thereby intimately associated with the onset and progression of many diseases. To ascertain the pathological roles of O 2 .− in related diseases, developing effective methods for monitoring O 2 .− in biological systems is essential. Fluorescence imaging is a powerful tool for monitoring bioactive molecules in cells and in vivo owing to its high sensitivity and high temporal‐spatial resolution. Therefore, increasing numbers of fluorescent imaging probes have been constructed to monitor O 2 .− inside live cells and small animals. In this minireview, we summarize the methods for design and application of O 2 .− ‐responsive fluorescent probes. Moreover, we present the challenges for detecting O 2 .− and suggestions for constructing new fluorescent probes that can indicate the production sites and concentration changes in O 2 .− as well as O 2 .− ‐associated active molecules in living cells and in vivo.