• A novel sandwich-type electrochemical DNA sensor based on PPY-rGO nanocomposites and AuNPs was developed for SARS-CoV-2 nucleic acid detection.
• The sensor leverages a sandwich hybridization strategy with capture and signal DNA probes, enhancing specificity and sensitivity.
• Electrochemical deposition and DPV enable quantitative detection of target DNA sequences with high accuracy.
• The PPY-rGO composite overcomes graphene limitations, offering improved conductivity and surface area for biosensing applications.