Improving immunoassay detection accuracy of anti-SARS-CoV-2 antibodies through dual modality validation

• Published in: Biosensors and bioelectronics. X 2022-09, Vol.11, p.100176-100176, Article 100176
• Main Authors: Ma, Yuhao, To, Daniel, Zeng, Jie, Shoute, Lian C.T., Wu, Meng, Babiuk, Shawn, Zhuo, Ran, Charlton, Carmen, Kanji, Jamil N., Babiuk, Lorne, Chen, Jie
• Format: Article
• Language: English
• Subjects: Anti-SARS-CoV-2 IgG; COVID-19; Electrochemical impedance spectroscopy (EIS); Fluorescence labeling; Serology testing
• ISSN: 2590-1370; 2590-1370
• DOI: 10.1016/j.biosx.2022.100176

A novel test strategy is proposed with dual-modality detection techniques for COVID-19 antibody detection. The full-length S protein of SARS-CoV-2 was chemically immobilized on a glass surface to capture anti-SARS-CoV-2 IgG in patient serum and was detected through either Electrochemical Impedance Spectroscopy (EIS) or fluorescence imaging with labeled secondary antibodies. Gold nanoparticles conjugated with protein G were used as the probe and the bound GNP-G was detected through EIS measurements. Anti-human-IgG conjugated with the fluorescent tag Alexa Fluor 488 was used as the probe for fluorescence imaging. Clinical SARS-CoV-2 IgG positive serum and negative controls were used to validate both modalities. For fluorescence-based detection, a high sensitivity was noticed with a quantification range of 0.01–0.1 A.U.C. and a LOD of 0.004 A.U.C. This study demonstrates the possibility of utilizing different measurement techniques in conjunction for improved COVID-19 serology testing. Detection of anti-SARS-CoV-2 antibodies through impedance and fluorescence validation. [Display omitted] •A dual modality detection based on impedance and fluorescence was proposed for SARS-CoV-2 IgG in clinical serum samples.•Both modalities were validated with clinical serum samples, with fluorescence detection giving a lower LOD.•The proposed method for SARS-CoV-2 Spike protein immobilization shows its advantage over physical coating.