ZnO Nanowire‐Based Early Detection of SARS‐CoV‐2 Antibody Responses in Asymptomatic Patients with COVID‐19

A serological immunoassay based on enzyme‐linked immunosorbent assay (ELISA) is a crucial tool for screening and identification of human SARS‐CoV‐2 seroconversion. Various immunoassays are developed to detect the spike 1 (S1) and nucleocapsid (NP) proteins of SARS‐CoV‐2; however, these serological tests have low sensitivity. Here, a novel microplate (MP) is developed on which a ZnO nanowire (NW) is fabricated by a modified hydrothermal synthesis method. This plate is coated with SARS‐CoV‐2 NP and used as a fluorescent immunoassay (FIA) to detect antibodies specific for SARS‐CoV‐2 NP. Compared with the bare MP, the ZnO‐NW MP binds high levels (up to 5 µg mL−1) of SARS‐CoV‐2 NP tagged to histidine without any surface treatment. A novel serological assay based on the ZnO‐NW MP is more sensitive than a commercial immunoassay, enabling early detection (within