An ECM-mimicking Bilayer Vascular Craft from Collagen Filaments and Nanofibers

摘要

In this study, an ECM-mimicking bilayer small-caliber vascular graft was successfully fabricated from only collagen filaments and nanofibers. The external knitted layer provided the grafts with comparable mechanical strength to the native blood vessels and superior cell recruitment, and the luminal electrospun layer of collagen nanofibers reduced the pore size and promoted endothelial cell proliferation. The collagen grafts showed significantly different mechanical behavior under dry and hydrated conditions, but their bursting strength and suture retention strength were comparable to autologous grafts. There was no significant difference between the single layer knitted collagen prototype and the bilayer samples with both a knitted outer layer and an electrospun luminal layer (p<0.05), indicating that the mechanical properties were controlled only by the knitted layer. HUVECs were seeded on the collagen grafts to evaluate their biological performance. The results from an alamar blue assay confirmed that the collagen grafts promoted cell adhesion and proliferation and the inner electrospun layer reduced the pore size significantly which improved the hemodynamic properties and promoted the proliferation of endothelial cells.