Rapid and reliable detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody can provide immunological evidence in addition to
nucleic acid test for the early diagnosis and on-site screening of
coronavirus disease 2019 (COVID-19). All-solid-state biosensor capable of rapid, quantitative SARS-CoV-2 antibody testing is still lacking. Herein, we propose an electronic labelling strategy of
protein molecules and demonstrate SARS-CoV-2
protein biosensor employing colloidal
quantum dots (CQDs)-modified
electrode. The feature current peak corresponding to the specific binding reaction of SARS-CoV-2
antigen and antibody
proteins was observed for the first time. The unique charging and discharging effect depending on the alternating voltage applied was ascribed to the quantum confinement, Coulomb blockade and quantum tunneling effects of
quantum dots. CQDs-modified
electrode could recognize the specific binding reaction between
antigen and antibody and then transduce it into significant electrical current. In the case of serum specimens from
COVID-19 patient samples, the all-solid-state
protein biosensor provides quantitative analysis of SARS-CoV-2 antibody with correlation coefficient of 93.8% compared to
enzyme-linked
immunosorbent assay (ELISA) results. It discriminates patient and normal samples with accuracy of about 90%. The results could be read within 1 min by handheld testing system prototype. The sensitive and specific
protein biosensor combines the advantages of rapidity, accuracy, and convenience, facilitating the implement of low-cost, high-throughput immunological diagnostic technique for clinical lab, point-of-care testing (POCT) as well as home-use test.