A simple and label-free electrochemical biosensor for DNA detection based on the super-sandwich assay.

The focus of this work was on designing a label-free DNA biosensor based on a super-sandwich assay using the electrochemical impedance spectroscopy technique. For this purpose, we designed a signal-up configuration whose linker probes could hybridize with two regions of the target DNA. In this configuration, the presented target DNA would effectively decrease the electron transfer, which would improve the sensitivity of the sensor. Ultimately, we employed gel electrophoresis to further confirm the formation of the proposed super-sandwich structure.