Controlled co-immobilization of EGF and VEGF to optimize vascular cell survival.

Growth factors (GFs) are potent signaling molecules that act in a coordinated manner in physiological processes such as tissue healing or angiogenesis. Co-immobilizing GFs on materials while preserving their bioactivity still represents a major challenge in the field of tissue regeneration and bioactive implants. In this study, we explore the potential of an oriented immobilization technique based on two high affinity peptides, namely the Ecoil and Kcoil, to allow for the simultaneous capture of the epidermal growth factor (EGF) and the vascular endothelial growth factor (VEGF) on a chondroitin sulfate coating. This glycosaminoglycan layer was selected as it promotes cell adhesion but reduces non-specific adsorption of plasma proteins. We demonstrate here that both Ecoil-tagged GFs can be successfully immobilized on chondroitin sulfate surfaces that had been pre-decorated with the Kcoil peptide. As shown by direct ELISA, changing the incubation concentration of the various GFs enabled to control their grafted amount. Moreover, cell survival studies with endothelial and smooth muscle cells confirmed that our oriented tethering strategy preserved GF bioactivity. Of salient interest, co-immobilizing EGF and VEGF led to better cell survival compared to each GF captured alone, suggesting a synergistic effect of these GFs. Altogether, these results demonstrate the potential of coiled-coil oriented GF tethering for the co-immobilization of macromolecules; it thus open the way to the generation of biomaterials surfaces with fine-tuned biological properties. STATEMENT OF SIGNIFICANCE: Growth factors are potent signaling molecules that act in a coordinated manner in physiological processes such as tissue healing or angiogenesis. Controlled coimmobilization of growth factors on biomaterials while preserving their bioactivity represents a major challenge in the field of tissue regeneration and bioactive implants. This study demonstrates the potential of an oriented immobilization technique based on two high affinity peptides to allow for the simultaneous capture of epidermal growth factor (EGF) and vascular endothelial growth factor (VEGF). Our system allowed an efficient control on growth factor immobilization by adjusting the incubation concentrations of EGF and VEGF. Of salient interest, co-immobilizing of specific ratios of EGF and VEGF demonstrated a synergistic effect on cell survival compared to each GF captured alone.