Digital and Analog Detection of SARS-CoV-2 Nucleocapsid Protein via an Upconversion-Linked Immunosorbent Assay

0570605 - ÚIACH 2024 RIV US eng J - Článek v odborném periodiku
Brandmeier, J. C. - Jurga, N. - Grzyb, T. - Hlaváček, Antonín - Obořilová, R. - Skládal, P. - Farka, Z. - Gorris, H. H.
Digital and Analog Detection of SARS-CoV-2 Nucleocapsid Protein via an Upconversion-Linked Immunosorbent Assay.
Analytical Chemistry. Roč. 95, č. 10 (2023), s. 4753-4759. ISSN 0003-2700. E-ISSN 1520-6882
Grant CEP: GA ČR(CZ) GA21-03156S
Institucionální podpora: RVO:68081715
Klíčová slova: SARS-CoV-2 * biopolymers * immunology * nucleocapsid protein * peptides and proteins,
Obor OECD: Analytical chemistry
Impakt faktor: 7.4, rok: 2022
Způsob publikování: Open access
https://pubs.acs.org/doi/pdf/10.1021/acs.analchem.2c05670

The COVID-19 crisis requires fast and highly sensitive tests for the early stage detection of the SARS-CoV-2 virus. For detecting the nucleocapsid protein (N protein), the most abundant viral antigen, we have employed upconversion nanoparticles that emit short-wavelength light under near-infrared excitation (976 nm). The anti-Stokes emission avoids autofluorescence and light scattering and thus enables measurements without optical background interference. The sandwich upconversion-linked immunosorbent assay (ULISA) can be operated both in a conventional analog mode and in a digital mode based on counting individual immune complexes. We have investigated how different antibody combinations affect the detection of the wildtype N protein and the detection of SARS-CoV-2 (alpha variant) in lysed culture fluid via the N protein. The ULISA yielded a limit of detection (LOD) of 1.3 pg/mL (27 fM) for N protein detection independent of the analog or digital readout, which is approximately 3 orders of magnitude more sensitive than conventional enzyme-linked immunosorbent assays or commercial lateral flow assays for home testing. In the case of SARSCoV-2, the digital ULISA additionally improved the LOD by a factor of 10 compared to the analog readout.
Trvalý link: https://hdl.handle.net/11104/0341909