posted on 2021-04-06, 18:04authored bySeunghyeon Kim, Yining Hao, Eric A. Miller, Dousabel M. Y. Tay, Emma Yee, Patthara Kongsuphol, Huan Jia, Megan McBee, Peter R. Preiser, Hadley D. Sikes
Rapid and inexpensive serological
tests for severe acute respiratory syndrome
coronavirus-2 (SARS-CoV-2) antibodies are essential to conduct large-scale
seroprevalence surveys and can potentially complement nucleic acid
or antigen tests at the point of care. During the COVID-19 pandemic,
extreme demand for traditional lateral flow tests has stressed manufacturing
capacity and supply chains. Motivated by this limitation, we developed
a SARS-CoV-2 antibody test using cellulose, an alternative membrane
material, and a double-antigen sandwich format. Functionalized SARS-CoV-2
antigens were used as both capture and reporter binders, replacing
the anti-human antibodies currently used in lateral flow tests. The
test could provide enhanced sensitivity because it labels only antibodies
against SARS-CoV-2 and the signal intensity is not diminished due
to other human antibodies in serum. Three-dimensional channels in
the assay were designed to have consistent flow rates and be easily
manufactured by folding wax-printed paper. We demonstrated that this
simple, vertical flow, cellulose-based assay could detect SARS-CoV-2
antibodies in clinical samples within 15 min, and the results were
consistent with those from a laboratory, bead-based chemiluminescence
immunoassay that was granted emergency use approval by the US FDA.