Eph receptors and ephrin ligands are essential for vascular development and angiogenic remodeling. In this work, we developed biomimetic poly(ethylene glycol)-diacrylate hydrogels incorporated with ephrin-Al and examined their angiogenic properties. Ephrin-Al was covalently immobilized on the surface of hydrogels by chemical modification and photopolymerization. Ephrin-Al immobilized on hydrogels was found to retain its capacity to stimulate endothelial cell adhesion in a dose-dependent manner as similar findings were observed on polystyrene culture wells pre-adsorbed with ephrin-Al. Cell adhesion stimulated by ephrin-Al was abolished by treatment with soluble RGDS and anti-a(nu)beta(3) integrin but not anti-a(nu)beta(5) integrin antibodies, suggesting that ephrin-Al activates cell adhesion through a(nu)beta(3) integrins. Also, surface immobilized ephrin-Al was found to induce endothelial tubule formation with luminal diameters ranging 5-30 mu m on hydrogels. The results of these studies demonstrate that pro-angiogenic properties of ephrin-Al are preserved in hydrogels and suggest potential applications of this hydrogel system in regenerative medicine and tissue engineering.