Practice question

Phage display biopanning involves cycles of binding, washing, and elution to enrich high-affinity binders from large libraries. After incubation of phage library with immobilized target, non-specific phages are removed by stringent washes. Specific bound phages remain attached via displayed protein interaction. Lowering pH with glycine-HCl buffer around pH 2.2 protonates interacting residues, disrupting electrostatic and hydrogen bonds at binding interface without destroying phage infectivity. Eluted phages are neutralized quickly and amplified in bacteria, enabling iterative enrichment for affinity maturation and ligand discovery.