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

The superoxide anion (O2 .- ) 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 O2 .- in related diseases, developing effective methods for monitoring O2 .- 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 O2 .- inside live cells and small animals. In this minireview, we summarize the methods for design and application of O2 .- -responsive fluorescent probes. Moreover, we present the challenges for detecting O2 .- and suggestions for constructing new fluorescent probes that can indicate the production sites and concentration changes in O2 .- as well as O2 .- -associated active molecules in living cells and in vivo.