Reliable Surface Modification of ePTFE Using a Photoreactive Hemocompatible Peptide to Promote Endothelial Affinity and Antiplatelet Efficacy

Expanded polytetrafluoroethylene (ePTFE) is a widely used material in diverse medical devices, particularly in the cardiovascular system, owing to its chemical stability and suitable mechanical properties. However, the chemical inertness makes surface modification difficult. In the present study, modification of ePTFE with a peptide was successfully achieved based on a unique photoreaction technique. We previously screened the hemocompatible peptide (HCP), histidine-glycine-glycine-valine-arginine-leucine-tyrosine (HGGVRLY), with high endothelial affinity and antiplatelet ability as modifying molecules. We synthesized a photoreactive peptide by combining a phenylazide group with the HCP, which was subsequently immobilized on the ePTFE surface through a short UV exposure time after argon plasma (Ar) treatment. Cross-sectional images of the surface modified with fluorescent-labeled photoreactive HCP showed efficient modification even within the pores of ePTFE. In vitro assessment revealed that modification improved the endothelial affinity of ePTFE approximately 5-fold while preventing platelet adhesion and aggregation. The ePTFE grafts were further implanted into an in situ porcine closed-circuit system for the blood contact assessment. Comparative investigations with untreated ePTFE grafts indicated that the modified ePTFE surface attracted more cells positive for CD14, CD16, CD34, and macrophage markers while concurrently exhibiting reduced platelet adhesion. In conclusion, photoreactive HCP proved to be a simple and effective strategy for modifying the ePTFE surface, resulting in enhanced hemocompatibility characterized by increased endothelial and monocyte recruitment as well as antiplatelet attachment on the modified ePTFE graft surface.