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

We herein developed a simple and ultrafast electrochemical DNA detection method by utilizing the oxidase-mimicking activity of cerium oxide nanoparticles (CeO2). In the sensor, the presence of DNA, which electrostatically interacts with CeO2 and 3,3', 5,5'-tetramethylbenzidine (TMB) substrate, limits the formation of CeO2-TMB complex that is required for the oxidase-like reaction. As a result, the oxidase-mimicking activity of CeO2 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.