A Dual-Functional Hydrogel Coating for Expanded Polytetrafluoroethylene Endografts with Antibacterial and Interface-Sealing Functions

Although expanded polytetrafluoroethylene (ePTFE) endografts provide excellent mechanical exclusion of aneurysm blood flow, they remain biologically inert and lack surface functions that actively prevent bacterial colonization or promote favorable graft-vessel interface responses following implantation. Here, we report a dual-functional hydrogel coating for ePTFE vascular grafts that integrates antibacterial protection with localized procoagulant activity at the graft-vessel interface. The coating, denoted as ZnO@CH, is prepared via in situ photopolymerization of methacryloyl-modified chitosan (CSMA) incorporating zinc oxide (ZnO) nanoparticles, forming a stable, spatially confined functional layer on the outer surface of ePTFE grafts. In vitro and in vivo evaluations demonstrate that the coating exhibits potent broad-spectrum antibacterial activity against Escherichia coli and methicillin-resistant Staphylococcus aureus while maintaining cytocompatibility with vascular endothelial cells. The ZnO@CH hydrogel promoted localized thrombus formation in a rat abdominal aorta model. Separately, an in vitro liquid-barrier assay showed that hydrogel-coated ePTFE retained its barrier function under the tested conditions. Systemic safety assessments in rodent models reveal no significant acute or chronic toxicity. Collectively, this dual-functional coating strategy offers a promising biomaterial approach for improving the biological performance of ePTFE vascular grafts.