Fig. 3.
(a) The calibration plots of ncovS1 sensor obtained against COVID-19 negative nasopharyngeal swab samples in SPS solution. Samples were diluted with PBS (1:99) and spiked with 50–400 fM (3.75–30 pg/ml) of ncovS1, (b) The calibration plot (solid line) of ncovS1 sensor obtained by linear regression of the averaged data in Fig. 3(a). The red squares represent data points corresponding to In measured by ncovS1 sensor against COVID-19 positive samples while the blue squares are those of negative samples. The error bars represent SDs of three measurements.