An overview of the latest graphene-based sensors for glucose detection: the effects of graphene defects

In this review, we analyze several types of graphene-based sensors for glucose detection with respect to their preparation, properties and efficiency in electrochemical processes. Graphene may display different types of defects, which play a role in the electron transfer processes. Oxygenated groups on the edges of graphene planes reduce the graphene in-plane conductivity, but may enhance the heterogeneous electron/proton transfer constant. Other positive effects of defects are related to the shortening of the distance between active centers and electrodes upon enzyme or protein immobilization. However, though by different mechanisms, all types of graphene enhance the electrochemical response at the electrode.