Evolution of Phage Display Approaches to Select Highly Specific Hemocompatible Peptides

The ideal blood-contacting surface would support endothelial cell lining and suppress platelet adhesion, but, in synthetic biomaterials, these issues often conflict with each other. The reconciliation of this dichotomy may arise by modifying the biomaterial surfaces with "smart" peptides. Phage display is a powerful method for discovering unique peptides capable of binding to target molecules, but the selection of peptides binding to intact cells is an intricate process. In fact, the target molecules are often hindered by the extremely complex composition of cell membrane. In this work, the traditional phage display screening approach against endothelial progenitor cells (EPCs) was implemented with the introduction of (1) a negative selection step against platelets and (2) the target affinity scoring function phage binding index. The peptide candidates were used to modify an expanded polytetrafluoroethylene (ePTFE) surface to demonstrate that one of them not only has high affinity for EPCs but also simultaneously decreases thrombus formation.