Ultrafast Electrochemical Sensor Based on Electrical Potential-Assisted Hybridization for Non-Amplification Determination of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) by Differential Pulse Voltammetry (DPV)

Abstract

A highly ultrafast and sensitive electrochemical sensor based on electrical potential-assisted hybridization was developed for the determination of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The electrode was modified with multi-walled carbon nanotubes (MWCNTs) and Au nanoparticles (AuNPs) for excellent electrochemical performance. The constant electric field was applied to rapidly and efficiently enrich the capture probes to the electrode surface in 60 s. Meanwhile, pyrene as the backfill reagent resulted in a significant reduction of nonspecific adsorption. The electrochemical properties of the modified electrode were investigated via electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The analytical response was measured by differential pulse voltammetry (DPV). The sensor achieved the ultrafast hybridization of nucleic acids at the electrode interface within 90 s, substantially reducing the reaction time from hours to minutes. Under optimal conditions, the sensor exhibited a superior detection limit of 60 fM and showed satisfactory specificity toward single-base mismatch. Additionally, the proposed sensor realized sensitive determination of SARS-CoV-2 in throat swabs. The enzyme-free and non-amplification sensing strategy showed promising potential for application in point-of-care testing (POCT).

Keywords:

• Differential pulse voltammetry (DPV)
• electrical potential-assisted hybridization
• point-of-care testing (POCT)
• severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)

Authors’ contributions

Qian Gao: Methodology, Data curation, Writing Review & Editing; Yang Li: Conceptualization, Review; Xinyi Li: Investigation; Huiqing Wang; Data curation; Lin Tian: Validation; Hao Gong: Data curation; Cuiping Ma: Formal analysis; Chao Shi: Methodology, Supervision, Funding acquisition, Resources, Review & Editing.

Disclosure statement

The authors declare that there are no competing interests associated with this manuscript.

Ethical approval

The authorized Human Health and Ethics Committee of the Affiliated Hospital of Qingdao University approved this study and all donors of the throat swabs provided informed consent. In addition, all methods were carried out in accordance with the relevant guidelines and regulations.

Additional information

Funding

This work was supported by the Science and Technology Benefiting the People Demonstration Project of Qingdao (22-2-7-smjk-2-nsh), the Natural Science Foundation of Shandong Province (ZR2023MC064, ZR2023MC166, ZR2023QD125), and the Key Project of Shandong Province Natural Science Foundation (ZR2020KH030).