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New Publication on COVID-19 immunoglobulin detection tests

Published on May 16, 2022 Updated on May 16, 2022

As early as April 2020, at the peak of the health crisis, the EMNS and LCO laboratories joined forces to respond to the Special Call COVID-19 ULB. Our researchers developed a rapid detection test using silver nanoparticles instead of gold nanoparticles. The results of their work have just been published in Analytical Chemistry.

Ultrastable Silver Nanoparticles for Rapid Serology Detection of Anti-SARS-CoV‑2 Immunoglobulins G.

Bryan Gosselin, Maurice Retout, Raphaël Dutour, Ludovic Troian-Gautier, Robin Bevernaegie, Sophie Herens, Philippe Lefèvre, Olivier Denis, Gilles Bruylants and Ivan Jabin, Analytical Chemistry (2022).

https://doi.org/10.1021/acs.analchem.2c00870   First published: 13 May 2022


Dipstick assays using silver nanoparticles (AgNPs) stabilized by a thin calix[4]arene-based coating were developed and used for the detection of Anti-SARS-CoV-2 IgG in clinical samples.
The calixarene-based coating enabled the covalent bioconjugation of the SARS-CoV-2 Spike Protein via the classical EDC/sulfo-NHS procedure. It further conferred remarkable stability to the resulting bioconjugated AgNPs, as no degradation was observed over several months. In comparison with lateral-flow immunoassays (LFIAs) based on classical gold nanoparticles, our AgNP-based system constitutes a clear step forward, as the limit of detection for Anti- SARS-CoV-2 IgG was reduced by 1 order of magnitude and similar signals were observed with 10 times fewer particles. In real clinical samples, the AgNP-based dipstick assays showed impressive results: 100% specificity was observed for negative samples, while a sensitivity of 73% was determined for positive samples. These values match the typical sensitivities obtained for reported LFIAs based on gold nanoparticles. These results (i) represent one of the first examples of the use of AgNP-based dipstick assays in the case of real clinical samples, (ii) demonstrate that ultrastable calixarene-coated AgNPs could advantageously replace AuNPs in LFIAs, and thus (iii) open new perspectives in the field of rapid diagnostic tests.

See also: Covid19@ULB: A new rapid detection test developed in the EMNS lab (17.12.20)