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

Autor:	Brandmeier JC; Department of Biochemistry, Faculty of Science, Masaryk University, 625 00 Brno, Czech Republic.; Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg, 93053 Regensburg, Germany., Jurga N; Department of Biochemistry, Faculty of Science, Masaryk University, 625 00 Brno, Czech Republic.; Department of Rare Earths, Faculty of Chemistry, Adam Mickiewicz University, Poznań, 61614 Poznań, Poland., Grzyb T; Department of Rare Earths, Faculty of Chemistry, Adam Mickiewicz University, Poznań, 61614 Poznań, Poland., Hlaváček A; Institute of Analytical Chemistry of the Czech Academy of Sciences, 602 00 Brno, Czech Republic., Obořilová R; Department of Biochemistry, Faculty of Science, Masaryk University, 625 00 Brno, Czech Republic., Skládal P; Department of Biochemistry, Faculty of Science, Masaryk University, 625 00 Brno, Czech Republic.; CEITEC - Central European Institute of Technology, Masaryk University, 625 00 Brno, Czech Republic., Farka Z; Department of Biochemistry, Faculty of Science, Masaryk University, 625 00 Brno, Czech Republic.; CEITEC - Central European Institute of Technology, Masaryk University, 625 00 Brno, Czech Republic., Gorris HH; Department of Biochemistry, Faculty of Science, Masaryk University, 625 00 Brno, Czech Republic.
Jazyk:	angličtina
Zdroj:	Analytical chemistry [Anal Chem] 2023 Mar 14; Vol. 95 (10), pp. 4753-4759. Date of Electronic Publication: 2023 Feb 27.
DOI:	10.1021/acs.analchem.2c05670
Abstrakt:	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 SARS-CoV-2, the digital ULISA additionally improved the LOD by a factor of 10 compared to the analog readout.
Databáze:	MEDLINE
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