Peptide Grafted Poly(Ethylene Glycol) Hydrogel as Biomaterial for Endothelial Colony Forming Cells

Abstract

Endothelial progenitor cells (EPCs) have the potential to become a reliable source of autologous cells for endothelialization of intravascular devices and vascularization of tissue engineered constructs. Endothelial colony forming cells (ECFCs) are one type of EPCs; ECFCs have a highly proliferative and differentiative nature and are capable of forming mature and functional endothelial cells for vessel repair and postnatal angiogenesis. However, currently little is currently known about the homing of these circulating ECFCs. This research investigated the rolling of ECFCs on peptide grafted hydrogels using a parallel plate flow chamber in order to mimic the dynamic adhesion of ECFCs under conditions simulating physiological arterial flow. Poly(ethylene glycol) diacrylate (PEGDA) was chosen to be the hydrogel backbone. Due to the ability of PEGDA to inhibit protein adsorption, it can be used as a "blank slate" to examine the specific interactions of cells with the covalently incorporated peptides. To assess the specific interactions required for ECFCs to interact with material coatings under shear, peptides including RGDS, REDV, YIGSR, and RGES were coupled to acryloyl-PEG and grafted onto the surface of PEG hydrogels. To study the effect of shear on cell rolling, the ECFC cell suspension was sheared over the hydrogels at rates of 20 s-1, 40 s-1, 80 s-1, and 120 s-1. ECFC rolling was significantly lower on REDV-grafted hydrogel. Migration experiments were also performed to examine the migration capability of ECFCs on the hydrogel surfaces. These results can be applied in the future for modification of biomaterial surfaces to enhance endothelialization.