Fig. 4.

Use of phage display libraries to identify peptides that bind to a specific organ. a The in vivo process is based on panning the library of peptides against the target organs. The phage peptide library is injected into the mouse’s tail vein to allow it to circulate throughout the body. After a few minutes in circulation, phage molecules that bind to organs and tissues of interest are isolated. The isolated phage molecules are amplified and subjected to further rounds of selection to enrich organ-specific phage. Finally, DNA from the phage is sequenced to identify the encoded peptide, and the peptide can be used for the development of organ-specific therapeutics and diagnostics. b The specificity of selected phage clones can be further confirmed using the phage homing assay. Mice are injected with the selected phage clones through the tail vein. Phage clones are allowed to circulate, and the nonspecific binders are washed out. The organs are subsequently recovered, and the titers of phage in various organs are determined