Bio-inspired anisotropic polymeric heart valves exhibiting valve-like mechanical and hemodynamic behavior
Bio-inspired anisotropic polymeric heart valves exhibiting valve-like mechanical and hemodynamic behavior
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DOI：
10.1007/s40843-019-1217-4
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发表时间：
2020-04-01
影响因子：
8.1
通讯作者：
Zhang, Xing
中科院分区：
文献类型：
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作者：
Guo, Feng;Liu, Chang;Zhang, Xing
具有层状纤维结构的天然心脏瓣膜小叶具有各向异性特征，使其能够承受长期心脏周期的复杂机械负荷。采用静电纺丝法制备了两种具有各向异性（ASF）和各向同性（ISF）性能的丝素（SF）纤维膜，并与聚乙二醇二丙烯酸酯（PEGDA）水凝胶结合，作为聚心瓣膜（PHV）替代品（PEGDA-ASF和PEGDA-ISF）。单轴拉伸试验表明，PEGDA-ASF在平行方向和垂直方向具有明显的反各向同性，弹性模量分别为10.95 +/- 1.09和3.55 +/- 0.32 MPa，而PEGDA-ISF具有各向同性，弹性模量为4.54 +/- 0.43 MPa。PEGDA-ASF和PEGDA-ISF的phv根据ISO 5840-3标准进行脉冲复制试验，显示出适当的水动力性能。然而，有限元分析（FEA）显示，各向异性PEGDA-ASF阀在舒张期裂隙处的最大主应力值（2.20 MPa）低于各向同性PEGDA-ISF阀（2.37 MPa）。在完全打开状态下，PEGDA-ASF瓣膜的弯曲区与天然瓣膜一样出现在腹部和附着线附近，而PEGDA-ISF瓣膜的弯曲区则接近自由边缘。高斯曲率分析还表明，各向异性PEGDA-ASF阀在开启过程中可以通过动态调节弯曲区域的移动来产生合适的表面形貌。因此，具有仿生层状纤维结构的phv的各向异性在模拟天然心脏瓣膜的力学和流体动力学行为中发挥了重要作用。
Native heart valve leaflets with layered fibrous structures show anisotropic characteristics, allowing them to withstand complex mechanical loading for long-term cardiac cycles. Herein, two types of silk fibroin (SF) fiber membranes with anisotropic (ASF) and isotropic (ISF) properties were prepared by electrospinning, and were further combined with poly(ethylene glycol) diacrylate (PEGDA) hydrogels to serve as polymeric heart valve (PHV) substitutes (PEGDA-ASF and PEGDA-ISF). The uniaxial tensile tests showed obvious ani-sotropy of PEGDA-ASF with elastic moduli of 10.95 +/- 1.09 and 3.55 +/- 0.32 MPa, respectively, along the directions parallel and perpendicular to the fiber alignment, while PEGDA-ISF possessed isotropic property with elastic moduli of 4.54 +/- 0.43 MPa. The PHVs from both PEGDA-ASF and PEGDA-ISF presented appropriate hydrodynamic properties from pulse duplicator tests according to the ISO 5840-3 standard. However, finite element analysis (FEA) revealed the anisotropic PEGDA-ASF valve showed a lower maximum principle stress value (2.20 MPa) in commissures during diastole compared with that from the isotropic PEGDA-ISF valve (2.37 MPa). In the fully open state, the bending area of the PEGDA-ASF valve appeared in the belly portion and near the attachment line like native valves, however, which was close to free edges for the PEGDA-ISF valve. The Gauss curvature analysis also indicated that the anisotropic PEGDA-ASF valve can produce appropriate surface morphology by dynamically adjusting the movement of bending area during the opening process. Hence, anisotropy of PHVs with bio-inspired layered fibrous structures played important roles in mechanical and hydrodynamic behavior mimicking native heart valves.