Isolating and Expanding Endothelial Progenitor Cells from Peripheral Blood on Peptide‐functionalized Polystyrene Surfaces

The expansion of human peripheral blood endothelial progenitor cells to obtain therapeutically relevant endothelial colony forming cells (ECFCs) has been commonly performed on xeno‐derived extracellular matrix proteins. For cellular therapy applications, xeno‐free culture conditions are desirable to improve product safety and reduce process variability. We have previously described a novel fluorophore‐tagged RGD peptide (RGD‐TAMRA) that enhanced the adhesion of mature endothelial cells in vitro. To investigate whether this peptide can replace animal‐derived extracellular matrix proteins in the isolation and expansion of ECFCs, peripheral blood mononuclear cells from 22 adult healthy adult donors were seeded on RGD‐TAMRA‐modified polystyrene culture surfaces. Endothelial colony formation was significantly enhanced on RGD‐TAMRA‐modified surfaces compared to the unmodified control. No phenotypic differences were detected between ECFCs obtained on RGD‐TAMRA compared to ECFCs obtained on rat tail collagen‐coated surfaces. Compared to collagen‐coated surfaces and unmodified surfaces, RGD‐TAMRA surfaces promoted ECFC adhesion, cell spreading, and clonal expansion. This work presents a platform that allows for a comprehensive in vitro evaluation of peptide‐based biofunctionalization as a promising avenue for ex vivo ECFC expansion.