Electrochemical assay of superoxide based on biomimetic enzyme at highly conductive TiO2 nanoneedles: from principle to applications in living cells.

A novel strategy for extremely durable, reliable, and selective in situ real-time determination of superoxide anion (O(2) (-)) based on direct electron transfer of a biomimetic superoxide dismutase (SOD), Mn(3)(PO(4))(2), at highly conductive TiO(2) nanoneedles is reported for the first time, and is further exploited for the determination of O(2) (-) from living normal and cancer ovary cells directly adhered onto the modified surface, suggesting that O(2) (-) might be proposed as a biomarker of cancer.