Sensitively detecting antigen of SARS-CoV-2 by a homogeneous immunoassay based on ortho-touch reaction and graphene oxide (GO) quenched acridine esterification chemiluminescence

In this study, a homogeneous immunoassay based on ortho-touch reaction and graphene oxide (GO) quenched acridine esterification chemiluminescence is developed for sensitive detection of SARS-CoV-2 antigen. The sensitivity and specificity of this method was further evaluated with viral protein, virus strains and clinical samples. Benefiting from strong chemiluminescence signal and good quenching performance of GO, this method allows enhanced signal-to-background ratio, and the limit of detection is down to 0.02 ng/ml of viral protein or equivalently 200 copies/ml of virus strains. In clinical evaluations, our approach demonstrated a high level of agreement with digital RT-PCR, achieving a positive coincidence rate of 90.87 %, a negative coincidence rate of 99.77 %, and an overall concordance of 96.53 %, while showing no cross-reactivity with other prevalent viruses. This method offers a promising, sensitive, rapid, and cost-effective platform for early SARS-CoV-2 diagnosis. Moreover, it can potentially be adapted for detecting other pathogens.