SARS-CoV-2 N Gene-Targeted Anodic Stripping Voltammetry Sensor Using a Novel CoS-NGQD/Pt@Pd Platform and Au-DNA-CdTe QD Probe

Abstract

Rapid screening of individuals infected with severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) is necessary to contain contagion in a large population. 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 nucleocapsid (N) gene of SARS-CoV-2 ribonucleic acid (RNA) of three variants (B.1.1.529, B.1.617.2, and B.1.351). A duplex-specific nuclease (DSN)-assisted highly selective release of signaling probes enable higher specificity, and an Au-supported DNA probe is incorporated to carry many CdTe QD signaling probes. After dissolution, the generated Cd2+ ions are 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 exhibits a wide range of detection (10 to 10(8) copies mu L-1) and a lower detection limit (0.12 copies mu L-1), without any amplification. The selectivity of the sensor is tested against MERS and HCoV-NL63, and real-time detection is performed on heat-inactivated viral samples, which show excellent selectivity.