A gold nanoparticle-protein G electrochemical affinity biosensor for the detection of SARS-CoV-2 antibodies: a surface modification approach

• Published in: Scientific reports Vol. 12; no. 1; p. 12850
• Main Authors: Khaniani, Yeganeh, Ma, Yuhao, Ghadiri, Mahdi, Zeng, Jie, Wishart, David, Babiuk, Shawn, Charlton, Carmen, Kanji, Jamil N, Chen, Jie
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group 27.07.2022; Nature Publishing Group UK; Nature Portfolio
• Subjects: Affinity; Antibodies; Biosensors; Coronaviruses; COVID-19; Electrochemistry; Enzyme-linked immunosorbent assay; Horseradish peroxidase; Immunoglobulin G; Impedance; Nanoparticles; Protein G; Proteins; Severe acute respiratory syndrome coronavirus 2
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-022-17219-7

Abstract As COVID-19 waves continue to spread worldwide, demand for a portable, inexpensive and convenient biosensor to determine community immune/infection status is increasing. Here we describe an impedance-based affinity biosensor using Interdigitated Electrode (IDE) arrays to detect antibodies to SARS-CoV-2 in serum. We created the biosensor by functionalizing the IDEs’ surface with abaculaovirus-expressed and purified Spike (S) protein to bind anti-SARS CoV-2antibodies. Gold nanoparticles (GNP) fused to protein G were used to probe for bound antibodies. An ELISA assay using horseradish peroxidase-protein G to probe for bound IgG confirmed that the purified S protein bound a commercial source of anti-SARS-CoV-2 antibodies specifically and bound anti-SARS-CoV-2 antibodies in COVID-19 positive serum. Then we demonstrated that our biosensor could detect anti-SARS-CoV-2 antibodies with 72% sensitivity in 2 h. Using GNP-protein G, the affinity biosensor had increased impedance changes with COVID-19positive serum and minimal or decreased impedance changes with negative serum. This demonstrated that our biosensor could discriminate between COVID-19 positive and negative sera, which were further improved using poly(vinyl alcohol)as a blocking agent.