Whole cell binding assay to screen ligands for binding to bladder cancer cells. For the whole cell binding assay, a single cell suspension was incubated with each OBOC library. Beads carrying ligands with affinity for cell surface molecules became covered with cells. In the middle of each panel, one positive bead was covered with bladder cancer cells, suggesting that the peptides on this bead could bind to bladder cancer cells. The cell lines, library types, and incubation time are shown next to each panel. The average bead diameter is approximately 90μm.