Fig. 1.

Increasing solution concentrations of Fc-containing ligand correlates to increasing surface ligand concentrations. Fluorescent images of surfaces prepared with increasing concentrations of Alexa Fluor-555 tagged human IgG₁ (IgG₁-555) mixed with unlabeled human IgG₁ to maintain a total protein concentration of 20 μg ml⁻¹. Solution concentrations of IgG₁-555 depicted are as follows: (A) 0 μg ml⁻¹, (B) 1 μg ml⁻¹, (C) 5 μg ml⁻¹, (D) 7.5 μg ml⁻¹, (E) 10 μg ml⁻¹, and (F) 15 μg ml⁻¹. (G) The pixel intensities were calculated for each concentration and plotted. Data reveals a linear correlation between soluble IgG₁-555 concentration and fluorescent signal present on the surface (R² = 0.991). Scale bar = 50 μm.