Heart valve substitute fabricated from silk protein, collagen, and poly‐glycerol sebacate has enhanced endothelial cell growth and reduced thrombogenicity

Abstract

Mechanical or collagen based porcine valves currently used to replace diseased or nonfunctional valves are subject to thrombosis, material failure, or inadequate in situ remodeling. In this study a new electrospun nanofiber composite was fabricated from mechanically robust silk fibroin, (F), Type I collagen (C), and the synthetic elastic polymer, poly (glycerol‐sebacate) (P). Materials fabricated with different weight ratios of F:C:P had an elastic modulus between 2.8–4.1 Mpa; tensile stresses from 1.1–1.5 Mpa and strains between 41–44% which were similar to values reported for native heart valve. In vitro degradation demonstrated <0.3% mass loss per week with no change in nanofiber diameter. In culture electrospun nanofibers mats of FCP compared to structurally similar C nanofibers had greater human umbilical vein endothelial cell growth and by confocal microscopy demonstrated tight intercellular junctions. Using human platelet rich plasma reduced platelet numbers were observed for FCP (3440 ± 302) (mean ± SEM, platelets/cm2)mats compared to C (5268 ± 848) and collagen gels (27,549 ± 698). By SEM, platelets appeared significantly less activated on FCP. Materials preseeded with cells had platelet adhesion of 555 ± 137, 1588 ± 41, and 12311 ± 208 respectfully for FCP, C, and collagen gels. The findings suggest FCP may be a superior material for heart valve replacement.