Rapid SARS-CoV-2 Detection Using Electrochemical Immunosensor

Abstract

The outbreak of the coronavirus disease (COVID-19) pandemic caused by the novel coronavirus (SARS-CoV-2) has been declared an international public health crisis. It is essential to develop diagnostic tests that can quickly identify infected individuals to limit the spread of the virus and assign treatment options. Herein, we report a proof-of-concept label-free electrochemical immunoassay for the rapid detection of SARS-CoV-2 virus via the spike surface protein. The assay consists of a graphene working electrode functionalized with anti-spike antibodies. The concept of the immunosensor is to detect the signal perturbation obtained from ferri/ferrocyanide measurements after binding of the antigen during 45 min of incubation with a sample. The absolute change in the [Fe(CN)6]3−/4− current upon increasing antigen concentrations on the immunosensor surface was used to determine the detection range of the spike protein. The sensor was able to detect a specific signal above 260 nM (20 µg/mL) of subunit 1 of recombinant spike protein. Additionally, it was able to detect SARS-CoV-2 at a concentration of 5.5 × 105 PFU/mL, which is within the physiologically relevant concentration range. The novel immunosensor has a significantly faster analysis time than the standard qPCR and is operated by a portable device which can enable on-site diagnosis of infection.

A Novel Method for the Detection of SARS-CoV-2 Based on Graphene-Impedimetric Immunosensor

“…Using the SWV technique, the proposed sensor detected a concentration of 2.40 ng/mL of the virus. This study shows the potential of the technique and the immunosensor proposed in the SARS-CoV-2 spike protein analysis at low concentrations [ 26 , 27 , 28 ].…”

Detection of SARS-CoV-2 and its S and N proteins using surface enhanced Raman spectroscopy

“…Several other methods based on nanotechnology and 2-D materials have also been reported. [10][11][12][13][14] A comprehensive review of the detection methods can be found in ref. 15-17. A general conclusion is that the methods, other than RT-PCR detection assays, have some limitations including low detection sensitivity and, thus, have not replaced RT-PCR as the gold standard.…”

Quantifying SARS-Cov-2 Nucleocapsid Antigen in Oropharyngeal Swabs Using Single Molecule Array Technology

“…A technical sensitivity equivalent to 20-100 RNA molecules/mL is also found when estimating from gure 2a. The upper level of detection was 10 5 RNA molecules/mL in both assays estimated from gure 2a. The technical sensitivity was further examined by preparing two real time RT-PCR positive swab samples in various dilutions and measuring using the Quanterix assay, ddPCR, and real time RT-PCR ( gure 2b).…”

“…To our knowledge, Quanterix did not plan to construct a SARS-CoV-2 antigen assay, we decided to develop an in-house SARS-CoV-2 antigen assay for the Simoa platform. Antigen methods for identifying SARS-CoV-2 focus on detection of the viral spike protein (5,6) or the nucleocapsid protein (7,8). Our early experiments revealed that nucleoprotein assays seemed to provide a superior diagnostic sensitivity as compared to spike protein assays.…”