GT70
Symposium: S01 - General Session Oral Presentation
Fabrication of Triple Layered Vascular Scaffolds by Combing Electrospinning, Braiding, and Thermally Induced Phase Separation
Mi Haoyang (1), Yu Emily (2), McNulty Jason (3), Peng Xiang-Fang (1), Turng Lih-Sheng (3)*
(1) South China University of Technology - Guangdong - China, (2) University of Wisconsin–Madison - WI - USA, (3) University of Wisconsin-Madison - WI - USA
Recently, the demand for small diameter (3–6 mm) vascular scaffolds has been growing due to their increased use especially in bypass surgeries for various cardiovascular diseases. Vascular tissue engineering provides an approach to fabricating artificial scaffolds that resemble native blood vessels. A native blood vessel consists of three different layers, i.e., intima, media, and adventitia, and each layer is comprised of different cells. Therefore, the fabrication of vascular scaffolds with a triple layered structure has attracted significant attention. Most multi-layered vascular scaffolds have been based on electrospinning various materials on top of each other. However, these vascular scaffolds lack cell penetration ability due to dense fibrous structure. Thermally induced phase separation (TIPS) can produce scaffolds with highly porous structures but poor mechanical properties. Braiding can be used to construct tubes with a textile structure and high mecha¬nical properties. In this study, triple layered small diameter vascular scaffolds, which consisted of thermoplastic polyurethane (TPU) and silk fiber, were fabricated by combining electrospinning, braiding, and TIPS methods. The morphology and mechanical properties of the triple layered scaffolds were characterized and compared to single and double layered scaffolds. These novel scaffolds, which possess a nanofibrous inner layer, woven silk filament middle layer, and porous outer layer have a desired toe region, sufficient suture retention, and burst pressure resistance for vascular graft applications. Human umbilical vein endothelial cells (HUVECs) were used to investigate the cellular response. The cell culture resulted in a cell layer forming on the inner scaffold surface with high cell viability. The braided silk filaments attracted even more cells. Furthermore, the cells showed a well stretched flat morphology with their pseudopodia spread out indicating favorable cellular–scaffold interactions.