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Published March 10, 2023 | Accepted Version + Published + Supplemental Material
Journal Article Open

Hybridization Chain Reaction Lateral Flow Assays for Amplified Instrument-Free At-Home SARS-CoV-2 Testing


The lateral flow assay format enables rapid, instrument-free, at-home testing for SARS-CoV-2. Due to the absence of signal amplification, this simplicity comes at a cost in sensitivity. Here, we enhance sensitivity by developing an amplified lateral flow assay that incorporates isothermal, enzyme-free signal amplification based on the mechanism of hybridization chain reaction (HCR). The simplicity of the user experience is maintained using a disposable 3-channel lateral flow device to automatically deliver reagents to the test region in three successive stages without user interaction. To perform a test, the user loads the sample, closes the device, and reads the result by eye after 60 min. Detecting gamma-irradiated SARS-CoV-2 virions in a mixture of saliva and extraction buffer, the current amplified HCR lateral flow assay achieves a limit of detection of 200 copies/μL using available antibodies to target the SARS-CoV-2 nucleocapsid protein. By comparison, five commercial unamplified lateral flow assays that use proprietary antibodies exhibit limits of detection of 500 copies/μL, 1000 copies/μL, 2000 copies/μL, 2000 copies/μL, and 20,000 copies/μL. By swapping out antibody probes to target different pathogens, amplified HCR lateral flow assays offer a platform for simple, rapid, and sensitive at-home testing for infectious diseases. As an alternative to viral protein detection, we further introduce an HCR lateral flow assay for viral RNA detection.

Additional Information

© 2023 The Authors. Published by American Chemical Society. Permits the broadest form of re-use including for commercial purposes, provided that author attribution and integrity are maintained (https://creativecommons.org/licenses/by/4.0/). We thank M. Schwarzkopf and K. S. Lee for performing preliminary studies. We thank M. E. Bronner for reading a draft of the manuscript. We thank M. Schwarzkopf, K. S. Lee, L. M. Hochrein, G. Shin, B. J. Wold, and R. F. Ismagilov for helpful discussions. We thank G. Shin of the Molecular Technologies resource within the Beckman Institute at Caltech for providing HCR reagents. This work was funded by the Shurl and Kay Curci Foundation, by the Richard N. Merkin Institute for Translational Research at Caltech, by the National Aeronautics and Space Administration (Translational Research Institute for Space Health; NNX16AO69A), and by the National Institutes of Health (NIBIB R01EB006192 and NIGMS training grant GM008042 to S.J.S.). Author Contributions. S.J.S. and J.H. contributed equally. The authors declare the following competing financial interest(s): Patents, pending patent applications, and the startup company Molecular Instruments.

Attached Files

Published - acsinfecdis2c00472.pdf

Accepted Version - id2c00472-acc.pdf

Supplemental Material - id2c00472_si_001.pdf

Supplemental Material - id2c00472_si_002.mp4

Supplemental Material - id2c00472_si_003.mp4


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Additional details

October 9, 2023
December 22, 2023