Fig. 5: Validation of p-LFA using an inexpensive, portable fluorescence scanner.

a, Photograph of the portable fluorescence scanner. b, Schematic illustration of the LFA cassette used in the study and the workflow of p-LFA. S, T and C correspond to the sample pad, test line and control line, respectively. The blue arrow represents the direction of the fluorescence measurements made on the LFA cassette using the portable scanner. c, Representative positive (black) and negative (red) signals obtained using the portable scanner. d, Fluorescence intensities (black spheres) and area under the curve values (red spheres) obtained from LFA strips, drop-casted with different concentrations of plasmonic fluors, scanned using benchtop and portable scanners. e, Eight-bit ImageJ-processed image of the full-strip IL-6 colorimetric p-LFA depicting the visual read-out mode. f, Fluorescence image of the full-strip IL-6 fluorometric p-LFA depicting the fluorescence read-out mode. g, Dose-dependent signal of 15 min IL-6 fluorometric p-LFA measured by benchtop (black) and portable scanners (red). h, Linear regression plot of IL-6 concentration in serum samples determined by fluorometric p-LFA and measured using the benchtop and portable scanners. i, Linear regression plot of IL-6 concentration in serum samples determined by 4 h lab-based p-FLISA and a benchtop fluorescence scanner, compared with measurements made using 15 min fluorometric p-LFA and the portable scanner. j, Linear regression plot of N protein concentration in NP swab samples determined by fluorometric p-LFA and measured using the benchtop and portable scanners. Data are mean ± s.d.; n = 2 × 2 repeated tests. Schematic was created with BioRender.com.