These are preliminary reports that have not been peer-reviewed. They should not be regarded as conclusive, guide clinical practice/health-related behavior, or be reported in news media as established information. For more information, please see our FAQs.
Preprints are manuscripts made publicly available before they have been submitted for formal peer review and publication. They might contain new research findings or data. Preprints can be a draft or final version of an author's research but must not have been accepted for publication at the time of submission.
submitted on 05.10.2020 and posted on 06.10.2020by Cody Carrell, Jeremy Link, Ilhoon Jang, James Terry, Michael Scherman, Zachary Call, Yosita Panraksa, David S. Dandy, Brian J. Geiss, Charles Henry
A disposable enzyme-linked immunosorbent assay (dELISA) device for ate-home or doctor’s
office use was developed to detect SARS-CoV-2 antibodies. Serology testing for SARS-CoV-2 antibodies
is currently run using well-plate ELISAs in centralized laboratories. However, the scale of serology testing
needed for epidemiological and clinical screening studies will overwhelm existing clinical laboratory
resources. Instead, a point-of-need device that can be used at home or in doctor’s offices for COVID-19
serology testing must be developed and is one of four target products prioritized by the World Health
Organization. Lateral flow assays are common and easy to use, but lack the sensitivity needed to reliably
detect SARS-CoV-2 antibodies in clinical samples. This work describes a disposable ELISA device that
is as simple to use as a lateral flow assay, but as sensitive as a well-plate ELISA. The device utilizes
capillary-driven flow channels made of transparency films and double-sided adhesive combined with
paper pumps to drive flow. The geometry of the channels and storage pads enables automated sequential
washing and reagent addition steps with two simple end-user steps. An enzyme label is used to produce a
colorimetric signal instead of a nanoparticle label in order to amplify signal and increase sensitivity, while
the integrated washing steps decrease false positives and increase reproducibility. Naked-eye detection
can be used for qualitative results or a smartphone camera for quantitative analysis. The device can detect
antibodies at 2.8 ng/mL from whole blood, which was very close the concentration of detectable target in
a well-plate ELISA (1.2 ng/mL). In this study the dELISA system was used to detect SARS-CoV-2
antibodies, but we believe that the device represents a fundamental step forward in point-of-care
technology that will enable sensitive detection of many other analytes outside of a centralized laboratory.