Figure 3
The limit of detection of the pipetting-based immunoassay for enzymatic colour development. (a) Limit of detection of the pipetting-based immunoassay for enzymatic colour development using 11 µg, 1.1 µg, 0.11 µg, and 0.011 µg/reaction of the recombinant NP in PBS (pH 7.4), and 106, 105, 104, 103, and 102 EID50/reaction of A/swine/Korea/P17-4/2017 isolate in PBS (pH 7.4). (b) Time-based colour development measured with two-fold diluted A/swine/Korea/P17-4/2017 isolate (107 EID50/mL), 106, 5 × 105, 2.5 × 105, 1.25 × 105, 6.25 × 104 EID50/reaction, and negative control as 10 times and 20 times diluted allantoic fluid of specific pathogen-free embryonated eggs with PBS (pH 7.4). The absorbance value of the colour-developed solution was measured at 650 nm in duplicates. (c) Comparison of the limits of detection among the pipetting-based immunoassays for enzymatic colour development and two commercial lateral flow kits (kits A and B).
