Fig. 1. Schematics and fluorescence signals of various concentrations of capture antibodies. (A) Schematic detection of sandwich immunoassay using Cy5-streptavidin as labelling. (B) Fluorescent intensities of antibody arrays at various concentrations of capture antibodies 10–300 μg mL⁻¹ with a volume of 25 nL (0.25–7.5 ng per spot) on each microarray spot for detecting 10⁶ CFU mL⁻¹ of E. coli O157:H7. Error bars show ± 1 std. dev. (n = 9). Inset shows Fluorescence images (scale bar = 2000 μm).