Fabrication of elastomeric scaffolds with curvilinear fibrous structures for heart valve leaflet engineering.
Fabrication of elastomeric scaffolds with curvilinear fibrous structures for heart valve leaflet engineering.
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DOI：
10.1002/jbm.a.35450
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发表时间：
2015-09
期刊：
影响因子：
--
通讯作者：
Wagner WR
中科院分区：
文献类型：
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作者：
Hobson CM;Amoroso NJ;Amini R;Ungchusri E;Hong Y;D'Amore A;Sacks MS;Wagner WR
自体半月心瓣膜由致密纤维网络组成，通常沿瓣叶宽度沿着曲线路径。工程瓣膜小叶的最新模型已经预测，这种曲线纤维取向将使应变场均匀化并减少连合处的应力集中。在目前的工作中，开发了一种方法，通过改变收集芯轴的几何形状来再现这种曲线纤维在静电纺丝支架中的排列。将弹性体聚（酯氨基甲酸酯）脲静电纺丝到不同角度的旋转锥形芯轴上以产生纤维支架，其中纤维排列的角度在支架长度上线性变化。通过使锥形心轴的半径与天然肺动脉瓣的曲率半径匹配，静电纺丝构造表现出与天然小叶类似的曲线纤维结构。此外，该结构具有与传统支架和天然心脏瓣膜相当的局部机械性能。与先前的建模结果一致，在准静态载荷下发现，与在传统圆柱形芯轴上产生的支架相比，曲线纤维微结构减少了应变集中。因此，这种简单的技术提供了一种有吸引力的手段，用于制造支架，其中天然小叶的关键微观结构特征被模仿用于心脏瓣膜组织工程。
Native semi-lunar heart valves are composed of a dense fibrous network that generally follows a curvilinear path along the width of the leaflet. Recent models of engineered valve leaflets have predicted that such curvilinear fiber orientations would homogenize the strain field and reduce stress concentrations at the commissure. In the present work, a method was developed to reproduce this curvilinear fiber alignment in electrospun scaffolds by varying the geometry of the collecting mandrel. Elastomeric poly(ester urethane)urea was electrospun onto rotating conical mandrels of varying angles to produce fibrous scaffolds where the angle of fiber alignment varied linearly over scaffold length. By matching the radius of the conical mandrel to the radius of curvature for the native pulmonary valve, the electrospun constructs exhibited a curvilinear fiber structure similar to the native leaflet. Moreover, the constructs had local mechanical properties comparable to conventional scaffolds and native heart valves. In agreement with prior modeling results, it was found under quasi-static loading that curvilinear fiber microstructures reduced strain concentrations compared to scaffolds generated on a conventional cylindrical mandrels. Thus, this simple technique offers an attractive means for fabricating scaffolds where key microstructural features of the native leaflet are imitated for heart valve tissue engineering.