Digital immunoassay for biomarker concentration quantification using solid-state nanopores

• Published in: Nature communications Vol. 12; no. 1; pp. 5348 - 11
• Main Authors: He, Liqun, Tessier, Daniel R., Briggs, Kyle, Tsangaris, Matthaios, Charron, Martin, McConnell, Erin M., Lomovtsev, Dmytro, Tabard-Cossa, Vincent
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 09.09.2021; Nature Publishing Group; Nature Portfolio
• Subjects: 45/71; 631/1647/664/1467; 631/57/2282; 631/61/350/1058; 639/925/926/1049; 82/1; 82/29; 9/10; 9/97; Biomarkers; Humanities and Social Sciences; Immunoassay; multidisciplinary; Optimization; Precision medicine; Proteins; Science; Science (multidisciplinary); Sensitivity; Solid state; Thyroid; Thyroid gland; Thyroid-stimulating hormone
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-25566-8

ABSTRACT Single-molecule counting is the most accurate and precise method for determining the concentration of a biomarker in solution and is leading to the emergence of digital diagnostic platforms enabling precision medicine. In principle, solid-state nanopores—fully electronic sensors with single-molecule sensitivity—are well suited to the task. Here we present a digital immunoassay scheme capable of reliably quantifying the concentration of a target protein in complex biofluids that overcomes specificity, sensitivity, and consistency challenges associated with the use of solid-state nanopores for protein sensing. This is achieved by employing easily-identifiable DNA nanostructures as proxies for the presence (“1”) or absence (“0”) of the target protein captured via a magnetic bead-based sandwich immunoassay. As a proof-of-concept, we demonstrate quantification of the concentration of thyroid-stimulating hormone from human serum samples down to the high femtomolar range. Further optimization to the method will push sensitivity and dynamic range, allowing for development of precision diagnostic tools compatible with point-of-care format. The concentration of a biomarker in solution can be determined by counting single molecules. Here the authors report a digital immunoassay scheme with solid-state nanopore readout to quantify a target protein and use this to measure thyroid-stimulating hormone from human serum.