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Developing a SARS-CoV-2 Antigen Test Using Engineered Affinity Proteins

submitted on 17.04.2021, 04:16 and posted on 19.04.2021, 10:33 by Seunghyeon Kim, Emma H. Yee, Eric A. Miller, Yining Hao, Dousabel M. Y. Tay, Ki-Joo Sung, Huan Jia, Joseph M. Johnson, Mohsan Saeed, Charles R. Mace, Deniz Yüksel Yurt, Hadley Sikes
The ongoing COVID-19 pandemic has clearly established how vital rapid, widely accessible diagnostic tests are in controlling infectious diseases and how difficult and slow it is to scale existing technologies. Here, we demonstrate the use of the rapid affinity pair identification via directed selection (RAPIDS) method to discover multiple affinity pairs for SARS-CoV-2 nucleocapsid protein (N-protein), a biomarker of COVID-19, from in vitro libraries in 10 weeks. The pair with the highest biomarker sensitivity was then integrated into a 10-minute, vertical-flow cellulose paper test. Notably, the as-identified affinity proteins were compatible with a roll-to-roll printing process for large-scale manufacturing of tests. The test achieved 40 pM and 80 pM limits of detection in 1×PBS (mock swab) and saliva matrices spiked with cell-culture generated SARS-CoV-2 viruses and is also capable of detection of N-protein from characterized clinical swab samples. Hence, this work paves the way towards the mass production of cellulose paper-based assays which can address the shortages faced due to dependence on nitrocellulose and current manufacturing techniques. Further, the results reported herein indicate the promise of RAPIDS and engineered binder proteins for the timely and flexible development of clinically relevant diagnostic tests in response to emerging infectious diseases.


Atlanta Center for Microsystems Engineered Point-of-Care Technologies (ACME POCT)

National Institute of Biomedical Imaging and Bioengineering

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National Research Foundation of Singapore

Deshpande Center for Technological Innovation


Email Address of Submitting Author


Massachusetts Institute of Technology


United States

ORCID For Submitting Author


Declaration of Conflict of Interest

DYY is an employee of 3M. JMJ is an employee of Quanterix Corporation.

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