COVID-19 Diagnosis and SARS-CoV‑2 Strain Identification by a Rapid, Multiplexed, Point-of-Care Antibody Microarray

Antigen tests to detect SARS-CoV-2 have emerged as a
promising
rapid diagnostic method for COVID-19, but they are unable to differentiate
between variants of concern (VOCs). Here, we report a rapid point-of-care
test (POC-T), termed CoVariant-SPOT, that uses a set of antibodies
that are either tolerant or intolerant to spike protein mutations
to identify the likely SARS-CoV-2 strain concurrent with COVID-19
diagnosis using antibodies targeting the nucleocapsid protein. All
reagents are incorporated into a portable, multiplexed, and sensitive
diagnostic platform built upon a nonfouling polymer brush. To validate
CoVariant-SPOT, we tested recombinant SARS-CoV-2 proteins, inactivated
viruses, and nasopharyngeal swab samples from COVID-19 positive and
negative individuals and showed that CoVariant-SPOT can readily distinguish
between two VOCs: Delta and Omicron. We believe that CoVariant-SPOT
can serve as a valuable adjunct to next-generation sequencing to rapidly
identify variants using a scalable and deployable POC-T, thereby enhancing
community surveillance efforts worldwide and informing treatment selection.