Redox indicator-based electrochemical DNA detection (Poster)

Screen-printed electrochemical sensors have gained considerable research interest in recent years due to their favorable properties in terms of sensitivity, analysis time, instrumentational simplicity, and cost-efficiency, which make them ideally suited for POC testing. Electrochemical DNA sensors are of particular interest due to the important role of nucleic acids as biomarker in disease diagnostics. As a result, a wide variety of novel electrochemical DNA sensing approaches have already been developed. Many of them rely on the use of DNA-binding redox indicators, the prerequisite being a different interaction with ssDNA and dsDNA. We investigated the suitability of the commonly used redox indicators [Ru(NH3)6]3+, methylene blue, AQMS, and AQDS for electrochemical detection of DNA hybridization on screen-printed sensors. For none of the redox indicators we observed a significant signal difference between ssDNA and dsDNA that would allow for detecting DNA hybridization. In contrast, an HRP-based electrochemical assay proved suitable for sensitive and specific target DNA detection due to enzymatic signal amplification and negligible current response in the absence of target DNA.