Development of a superoxide sensor by immobilization of superoxide dismutase

Superoxide (O2−, one of the reactive oxygen species (ROS)) produced in vivo plays various pathphysiological and physiological roles, and thus it is of great importance and value to evaluate quantitatively dynamic changes in superoxide concentration. We thus aimed at developing a superoxide dismutase (SOD)-immobilized sensor. Using a batch cell, the amount of superoxide produced via oxidation of hypoxanthine by xanthine oxidase (XOD) was quantitatively determined based on the measured electrical current. The peak current increased linearly with hypoxanthine concentration (0–100 μM, r2=0.99). Using a flow cell, the concentration of superoxide produced from the isolated heart of an endotoxin-administered rat was successfully measured. Overall, the new superoxide sensor demonstrated satisfying performance and reproducibility for the tissue-derived superoxide.