Fig. 1: Schematic diagram of the sVNT for SARS-CoV-2.

The capture reagent is a DIG-labeled RBD (red) that binds to the anti-DIG antibody attached to the GNR wall (blue). Capture-protein-specific antibodies (gold) in the serum compete with His-tagged ACE-2 (brown and orange) to decrease the signal. The ACE-2-His bound to the DIG-labeled RBD is measured using a biotinylated anti-His antibody (pink) that produces a fluorescent signal when the biotin binds to a fluorescent streptavidin conjugate (green).