Progress on Electrochemical Determination of Superoxide Anion

Superoxide anion (O-2(center dot-)) is the primary species of the reactive oxygen species (ROS), resulting from the metabolism of O-2 in the living organisms. Its dynamic changes can provide broad implications in physiological and pathological conditions. Therefore, the analytical methods that can determine O-2(center dot-) real-time and in vivo are receiving more and more attention. In light of these requirements, electrochemical approaches are the most promising candidate technologies in analysis of O-2(center dot-) due to their simplicity, direct measurements, and ease of miniaturation. This review summarizes the recent progress on electrochemical analysis of O-2(center dot-) taking into consideration toward the key issues: design of the electrolyte/electrode interface, direct electron transfer of enzymes, and applications in live cells and animals.