Electrochemical\nSignatures as a Diagnostic Tool for\nSARS-CoV-2 and Its Variant Detection in Real-Time Wastewater Samples

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