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

AbstractRapid 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 108 copies µL−1) and a lower detection limit (0.12 copies µL−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.