Fig. 1.

A) GC-FP biosensor chip shown with gasket and fluidic cover attached. B) COVID-19 antigens or control proteins were spotted onto GC-FP biosensor chips, then assessed for antibody binding from human blood samples. Subsequent labeling with Alexa Fluor 647 tagged anti-human IgG was used for the enhanced fluorescence detection output. C) Enhanced fluorescence images of GC-FP biosensor chips (v1) processed with negative control serum (blood serum collected >2 years prior to the COVID-19 pandemic and serum from subjects who were >2 weeks convalescent from PCR-confirmed COVID-19 infection. Boxes with dotted outlines indicate paired spots of key COVID-19/SARS CoV-2 antigens, S1, S1S2, and Nuc.