Yu E, Zhang J, Thomson J A, Turng L-S
Department of Mechanical Engineering, University of Wisconsin-Madison, Madison, WI, USA.
Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, USA.
Int Polym Process. 2016 Nov;31(5):638-646. doi: 10.3139/217.3247.
The demand for small-diameter blood vessel substitutes has been increasing due to a shortage of autograft vessels and problems with thrombosis and intimal hyperplasia with synthetic grafts. In this study, hybrid small-diameter vascular grafts made of thermoplastic polyurethane (TPU) and silk fibroin, which possessed a hybrid fibrous structure of an aligned inner layer and a random outer layer, were fabricated by the electrospinning technique using a customized striated collector that generated both aligned and random fibers simultaneously. A methanol post-treatment process induced the transition of fibroin protein conformation from the water-soluble, amorphous, and less ordered structures to the water-insoluble β-sheet structures that possessed robust mechanical properties and relatively slow proteolytic degradation. The methanol post-treatment also created crimped fibers that mimicked the wavy structure of collagen fibers in natural blood vessels. Ultrafine nanofibers and nanowebs were found on the electrospun TPU/fibroin samples, which effectively increased the surface area for cell adhesion and migration. Cyclic circumferential tensile test results showed compatible mechanical properties for grafts made of a soft TPU/fibroin blend compared to human coronary arteries. In addition, cell culture tests with endothelial cells after 6 and 60 days of culture exhibited high cell viability and good biocompatibility of TPU/fibroin grafts, suggesting the potential of applying electrospun TPU/fibroin grafts in vascular tissue engineering.
由于自体移植血管短缺以及合成移植物存在血栓形成和内膜增生问题，对小直径血管替代物的需求一直在增加。在本研究中，采用定制的条纹收集器通过静电纺丝技术制备了由热塑性聚氨酯（TPU）和丝素蛋白制成的混合小直径血管移植物，该收集器能同时产生排列的内层和随机的外层的混合纤维结构。甲醇后处理过程促使丝素蛋白构象从水溶性、无定形和无序结构转变为具有强大机械性能和相对缓慢蛋白水解降解的水不溶性β-折叠结构。甲醇后处理还产生了卷曲纤维，模仿了天然血管中胶原纤维的波浪结构。在静电纺丝的TPU/丝素蛋白样品上发现了超细纳米纤维和纳米网，这有效地增加了细胞粘附和迁移的表面积。循环周向拉伸试验结果表明，与人类冠状动脉相比，由柔软的TPU/丝素蛋白混合物制成的移植物具有相容的机械性能。此外，对内皮细胞进行6天和60天培养后的细胞培养测试显示，TPU/丝素蛋白移植物具有高细胞活力和良好的生物相容性，表明静电纺丝TPU/丝素蛋白移植物在血管组织工程中的应用潜力。
