Highly Compliant Vascular Grafts with Gelatin-Sheathed Coaxially Structured Nanofibers

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• 作者：Naveen Nagiah ; Richard Johnson ; Roy Anderson ; Winston Elliott ; Wei Tan
• 刊名：Langmuir
• 出版年：2015
• 出版时间：December 1, 2015
• 年：2015
• 卷：31
• 期：47
• 页码：12993-13002
• 全文大小：590K
• ISSN：1520-5827

文摘

We have developed three types of materials composed of polyurethane鈥揼elatin, polycaprolactone鈥揼elatin, or polylactic acid鈥揼elatin nanofibers by coaxially electrospinning the hydrophobic core and gelatin sheath with a ratio of 1:5 at fixed concentrations. Results from attenuated total reflection-Fourier transformed infrared spectroscopy demonstrated the gelatin coating around nanofibers in all of the materials. Transmission electron microscopy images further displayed the core鈥搒heath structures showing the core-to-sheath thickness ratio varied greatly with the highest ratio found in polyurethane-gelatin nanofibers. Scanning electron microscopy images revealed similar, uniform fibrous structures in all of the materials, which changed with genipin cross-linking due to interfiber interactions. Thermal analyses revealed varied interactions between the hydrophilic sheath and hydrophobic core among the three materials, which likely caused different core鈥搒heath structures, and thus physicomechanical properties. The addition of gelatin around the hydrophobic polymer and their interactions led to the formation of graft scaffolds with tissue-like viscoelasticity, high compliance, excellent swelling capability, and absence of water permeability while maintaining competent tensile modulus, burst pressure, and suture retention. The hydrogel-like characteristics are advantageous for vascular grafting use, because of the capability of bypassing preclotting prior to implantation, retaining vascular fluid volume, and facilitating molecular transport across the graft wall, as shown by coculturing vascular cells sandwiched over a thick-wall scaffold. Varied core鈥搒heath interactions within scaffolding nanofibers led to differences in graft functional properties such as water swelling ratio, compliance, and supporting growth of cocultured vascular cells. The PCL鈥揼elatin scaffold with thick gelatin-sheathed nanofibers demonstrated a more compliant structure, elastic mechanics, and high water swelling property. Our results demonstrate a feasible approach to produce new hybrid, biodegradable nanofibrous scaffold biomaterials with interactive core鈥搒heath structure, good biocompatibility, and tissue-like viscoelasticity, which may reduce potential problems with the use of individual polymers for vascular grafts.