Rapid and label-free, electrochemical DNA detection utilizing the oxidase-mimicking activity of cerium oxide nanoparticles

Abstract We herein developed a simple and ultrafast electrochemical DNA detection method by utilizing the oxidase-mimicking activity of cerium oxide nanoparticles (CeO 2 ). In the sensor, the presence of DNA, which electrostatically interacts with CeO 2 and 3,3′,5,5′-tetramethylbenzidine (TMB) substrate, limits the formation of CeO 2 -TMB complex that is required for the oxidase-like reaction. As a result, the oxidase-mimicking activity of CeO 2 is not effectively exerted, leading to the significantly diminished electrochemical current signal. With this novel strategy, we successfully determined DNA amplicon derived from Escherichia coli ( E . coli ) with the total assay time less than 6 min even without the post-purification of DNA amplicon.