Peroxidase Mimetic Activity at Tailored Nanocarbon Electrodes

We demonstrate here the intrinsic reactivity of nitrogen-doped carbon nanotubes (N-CNTs) toward H2O2 consumption and their use as a potential peroxidase mimetic. Analysis of N-CNTmodified glassy carbon electrodes in an rotating disk electrode (RDE) amperometry configuration indicates that the mechanism of H2O2 consumption is not a 2-electron reduction to H2O, as is observed for peroxidase-catalyzed H2O2 reduction. We believe that the N-CNT reaction mechanism toward H2O2 occurs through the decomposition of H2O2 to O2 and H2O, resulting in an increase in current at the N-CNT electrode as the newly generated H2O2 is electrochemically reduced. We have exploited this intrinsic reactivity by incorporating N-CNTs as a substitute for horseradish peroxidase (HRP) in a traditionally bi-enzymatic sensing scheme for the detection of glucose. These studies serve as proof of concept for the use of N-CNTs as a peroxidase mimetic in unmediated biogenic analyte detection.