For development of a new ligand-directed pharmacology, it is critical to measure delivery of
targeted drug ligands via molecular imaging or diagnostic readouts (termed theranostics).
Combinatorial peptide libraries serve as unbiased functional screens that can identify
specific peptides targeting cell-surface receptors accessible to the circulation. As candidate
drug leads, such peptides provide motifs likely to modify ligand-receptor interactions and
downstream signal transduction pathways. This strategy is synergistic with genomic and …