Fig. 4
Validation of immunomolecular assay for intact SARS-CoV-2 particles. a Linear regression for the assay. When the SARS-CoV-2 pseudovirus titer ranged between 6 × 102 and 6 × 107 TU/mL, a linear relationship occurred between the quantification Cq value and its titer (log-transformed) in the immunomolecular assay. y = − 2.537x + 40.02, R2 = 0.99. b Specificity of the assay. Twenty-four of the carboxyl magnetic beads with CQ25 antibody complexes (MB-CQ25) and 24 captured pseudovirus samples were used to evaluate the assay specificity. ****P < 0.0001. c Interference from HBV supernatant from AD38 cells and patient serum with different titers of HBV. d SARS-CoV-2 pseudovirus stability under different conditions. Viruses were applied to copper, aluminum, paper, and plastic maintained at 21–23 °C and 40% relative humidity over seven days. The titer of viable virus was expressed as log10-tranformed. Plots show the means and standard errors (I bars) of three replicates