Fig. 4: Lateral flow assay for influenza A detection.
a Illustration of assay process for the scattering-utilising LFIA. b Photograph showing the signal transition from absorption-based to scattering-utilising. t1 = 0 s, t2 = 15 s, t3 = 18 s, t4 = 27 s. c Graph showing the performance of detecting influenza A viral particles with a black-background LFIA (scattering-utilising LFIA) and conventional LFIA. The intensities were calculated as | the average signal value within 10% of the peak intensity—the average background signal value |. The spots and error bars indicate average and standard deviation, respectively. Three independent samples were analysed (n = 3). d Colourimetric images of LFIAs after detecting influenza A viral particles. e Comparison of LoD and detection range of scattering-utilising LFIA, commercial LFIA kits (the products were approved by the Ministry of Food and Drug Safety in the Republic of Korea), and qRT-PCR. In the graph, the three products were denoted as products A-C; conventional LFIA (fabricated in our group), scattering-utilising LFIA, and qRT-PCR were denoted as D, E, and F, respectively. Boxes indicate the detection range. f Selectivity test results for the scattering -utilising LFIA. Concentrations of viral particles: SARS-CoV-2 at 1000 TCID50 mL–1, RSV at 1000 TCID50 mL–1, influenza B at 1000 pfu mL–1, influenza A H1N1 at 1000 pfu mL–1 and H3N2 at 1000 pfu mL–1. Mix contains all samples of the same concentration. The data in the graphs are presented as the mean ± standard deviation (s.d.); n = 3 independent samples. LFIA lateral flow immunoassay, LoD limit of detection, RSV respiratory syncytial virus.
