A novel strategy for extremely durable, reliable, and selective in situ real-time determination of superoxide anion (O2˙−) based on direct electron transfer of a biomimeticsuperoxide dismutase (SOD), Mn3(PO4)2, at highly conductive TiO2 nanoneedles is reported for the first time, and is further exploited for the determination of O2˙− from living normal and cancer ovary cells directly adhered onto the modified surface, suggesting that O2˙− might be proposed as a biomarker of cancer.
