Fig. 2.
Selective antibody detection. (a) Initial data acquired after washing the spotted sample. Initial heights of the spots were measured to be ≈0.5 nm for BSA spots, ≈1.2 nm for rabbit IgG spots, and ≈1 nm for mouse IgG spots, corresponding to 0.5 ng/mm2, 1.2 ng/mm2, and 1 ng/mm2 of material density on the surface, respectively. All subsequent data were referenced to the initial spotted sample to track the relative biomolecule accumulation. Height information of each image is scaled equally, which is shown with the gray-level scale bar. (b) After subtraction of the reference image. (c) Anti-rabbit incubation. Binding was detected as a 2.5 ng/mm2 incremental surface accumulation at the rabbit IgG spots after 5 μg/ml goat anti-rabbit IgG incubation. (d) Anti-mouse incubation. A 1.5 ng/mm2 incremental surface accumulation at the mouse IgG spots was detected after 5 μg/ml goat anti-mouse IgG incubation.