Electrochemical Signatures as a Diagnostic Tool for SARS-CoV-2 and Its Variant Detection in Real-Time Wastewater Samples

The global outbreak of SARS-CoV-2/COVID-19 has significantly affected public health and healthcare systems, highlighting the urgent need for fast and sensitive COVID-19 detection methods. In this study, an electrochemical setup utilizing bare electrodes was developed to detect viral RNA in real-time samples. Initially, individual nucleotides (adenosine, guanosine, and cytidine) were analyzed at varying concentrations to predict the detection sensitivity of cell. Subsequently, different concentrations of a synthetic COVID-19 sample containing the E-gene were analysed, and changes in electrochemical current were detected with a linear relationship between E-gene copies and reduction peak current intensity. This electrochemical setup capability was further validated by detecting the viral genome in wastewater, with a distinct electrochemical signatures. Especially, the electrochemical system demonstrated nearly 99% accuracy in distinguishing between positive and negative samples, depicting high sensitivity and precision for detecting COVID-19 and its variants. A peak voltage shift in fast-scan cyclic voltammograms was observed for B.1.1 and B.1.1.7 (0.12 to 0.15 V) and for B.1.1.5 and B.1.1.6 variants (0.06 to 0.08 V), indicating a viable approach for rapid detection of COVID-19 and its variants. This electrochemical sensor-based technology could enhance pathogen detection capability in sewage and improve environmental health monitoring from one health perspective.