SARS CoV2 N Gene-Targeted Anodic Stripping Voltammetry Sensor Using a Novel CoS-NGQD/Pt@Pd Platform and Au-DNA-CdTe QD Probe

Rapid screening of individuals infected with severe acute respiratory syndrome-coronavirus-2 (SARS CoV2) is necessary to contain contagion in a large population. However, serology-based rapid screening assays are not effective for the early detection of viruses, due to the insufficient presence of antigens and antibodies. Nucleic acid-based gold standard assays are time-consuming, and nucleic acid amplification is mandatory and expensive, impeding the containment of the coronavirus disease 2019 (COVID-19) outbreak. To overcome the aforementioned disadvantages, this study deals with a specially designed gold (Au)-deoxyribonucleic acid (DNA)-cadmium telluride (CdTe) quantum dot (QD) probe to target two sections of the N gene of SARS CoV2 ribonucleic acid (RNA) of three variants (Omicron, delta, and beta). A duplex-specific nuclease (DSN)-assisted highly selective release of signaling probes enabled higher specificity, and an Au-supported DNA probe was incorporated to carry many CdTe QD signaling probes. After dissolution, the generated Cd2+ ions were quantified at the novel cobalt sulfide (CoS)-nitrogen-doped graphene QD (NGQD)/ Platinum (Pt)@Palladium (Pd) electrode with extraordinary sensitivity through square wave anodic stripping voltammetry (SWASV). The developed sensor exhibited a wide range of detection (10 to 108 copies μL-1) and a lower detection limit (0.12 copies μL-1), without any amplification than other the reported nucleic acid-based assays. The selectivity of the sensor was tested against MERS and HCoV-NL63, and real-time detection was performed on heat-inactivated viral samples, which showed excellent selectivity. The feasibility of the sensor was monitored by hyperspectral imaging analysis of DNA-RNA hybridization and DSN activity.