Peptide sequences mediating tropism to intact blood-brain barrier: An in vivo biodistribution study using phage display

► Cyclic-7mer peptides displaying brain tropism were identified by in vivo phage display. ► 349 unique peptides were associated with gray matter (microvasculature and parenchyma). ► Amino acid distribution suggested a theoretical ideal peptide sequence PP(S/P)SSST. ► Phage displaying SYTSSTM were recovered at highest frequency from brain gray matter. ► SYTSSTM phage showed a 5-fold greater brain accumulation compared to control phage.