Department of Cardiac Surgery, Ludwig Maximilians University Munich;
Department of Cardiac Surgery, Ludwig Maximilians University Munich; Chair of Medical Materials and Implants, Technical University Munich.
J Vis Exp. 2022 Mar 23(181). doi: 10.3791/63604.
Electrospinning has become a widely used technique in cardiovascular tissue engineering as it offers the possibility to create (micro-)fibrous scaffolds with adjustable properties. The aim of this study was to create multilayered scaffolds mimicking the architectural fiber characteristics of human heart valve leaflets using conductive 3D-printed collectors. Models of aortic valve cusps were created using commercial computer-aided design (CAD) software. Conductive polylactic acid was used to fabricate 3D-printed leaflet templates. These cusp negatives were integrated into a specifically designed, rotating electrospinning mandrel. Three layers of polyurethane were spun onto the collector, mimicking the fiber orientation of human heart valves. Surface and fiber structure was assessed with a scanning electron microscope (SEM). The application of fluorescent dye additionally permitted the microscopic visualization of the multilayered fiber structure. Tensile testing was performed to assess the biomechanical properties of the scaffolds. 3D-printing of essential parts for the electrospinning rig was possible in a short time for a low budget. The aortic valve cusps created following this protocol were three-layered, with a fiber diameter of 4.1 ± 1.6 µm. SEM imaging revealed an even distribution of fibers. Fluorescence microscopy revealed individual layers with differently aligned fibers, with each layer precisely reaching the desired fiber configuration. The produced scaffolds showed high tensile strength, especially along the direction of alignment. The printing files for the different collectors are available as Supplemental File 1, Supplemental File 2, Supplemental File 3, Supplemental File 4, and Supplemental File 5. With a highly specialized setup and workflow protocol, it is possible to mimic tissues with complex fiber structures over multiple layers. Spinning directly on 3D-printed collectors creates considerable flexibility in manufacturing 3D shapes at low production costs.
静电纺丝已成为心血管组织工程中广泛使用的技术，因为它提供了创造具有可调节性能的（微）纤维支架的可能性。本研究的目的是使用导电 3D 打印收集器创建模仿人心脏瓣膜叶纤维特征的多层支架。使用商业计算机辅助设计 (CAD) 软件创建主动脉瓣叶模型。使用导电聚乳酸制造 3D 打印的瓣叶模板。这些瓣叶负模被集成到专门设计的旋转静电纺丝心轴中。将三层聚氨酯纺到收集器上，模仿人心脏瓣膜的纤维取向。使用扫描电子显微镜 (SEM) 评估表面和纤维结构。荧光染料的应用还允许对多层纤维结构进行微观可视化。进行拉伸测试以评估支架的生物力学性能。在短时间内，为低预算实现了静电纺丝装置关键部件的 3D 打印。按照该方案制造的主动脉瓣叶为三层，纤维直径为 4.1±1.6μm。SEM 成像显示纤维均匀分布。荧光显微镜显示具有不同取向纤维的各个层，每个层都精确地达到所需的纤维结构。所生产的支架具有较高的拉伸强度，尤其是在取向方向上。不同收集器的打印文件可作为补充文件 1、补充文件 2、补充文件 3、补充文件 4 和补充文件 5 获得。通过高度专业化的设置和工作流程协议，可以在多层上模仿具有复杂纤维结构的组织。直接在 3D 打印收集器上纺丝可在低制造成本下为制造 3D 形状提供极大的灵活性。
