Real-time monitoring of superoxide accumulation and antioxidant activity in a brain slice model using an electrochemical cytochrome c biosensor

► Superoxide levels were examined in a mouse hippocampal brain slice model of ischemia. ► Electrochemical measurements provide evidence for extracellular superoxide release. ► Specificity of the response was demonstrated via addition of superoxide dismutase. ► Nanoceria may be a promising therapeutic agent for the treatment of ischemic injury.