Phage binding to NV VLPs. NV VLPs (5, 2.5, 1.25, and 0.63 μg) or 5 μg of unrelated protein BSA was immobilized, and the binding of each phage, indicated on the x axis, was detected by M13 phage antibody. The signal at optical density at 450 nm (OD450) is indicated on the y axis.