The effects of collagen fiber orientation on the flexural properties of pericardial heterograft biomaterials
The effects of collagen fiber orientation on the flexural properties of pericardial heterograft biomaterials
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DOI：
10.1016/j.biomaterials.2004.03.004
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发表时间：
2005-03-01
期刊：
影响因子：
14
通讯作者：
Sacks, MS
中科院分区：
文献类型：
--
作者：
Mirnajafi, A;Raymer, J;Sacks, MS
利用异种移植生物材料改善心脏瓣膜生物假体（BHV）需要更好地了解其力学行为。弯曲是瓣膜手术期间BHV瓣叶的主要变形模式，与拉伸载荷相比，在组织内引起更复杂的变形模式。在这项研究中，我们研究了胶原纤维的首选方向和由此产生的弯曲性能的本地和戊二醛处理的牛心包之间的关系。从预先分类的牛心包片上切下20圈× 4 mm的条，并分为四组：两组天然和化学处理标本中胶原纤维取向的两个方向。使用三点弯曲技术（ASAIO J. 45（1999）59）在两个不同方向上弯曲样本，并比较其弯曲机械响应。结果表明：（1）在天然和化学固定组中，所施加的挠曲力矩与样本曲率变化之间的关系均为非线性，（2）在天然和化学固定样本中，当牛心包向心包外膜或内脏表面挠曲时，挠曲特性无方向差异，（3）天然和化学固定的牛心包在垂直于局部首选胶原纤维方向弯曲时更硬;（4）化学固定增加了牛心包的弯曲刚度。本研究的结果表明，牛心包的弯曲性能主要是由纤维间的交联，而不是胶原纤维本身的刚度。这些发现可用于指导寻求优化异种移植生物材料的生物力学性能的新型化学处理方法的开发。(C)2004爱思唯尔有限公司保留所有权利。
Improving cardiac valve bioprostheses (BHV) utilizing heterograft biomaterials requires a better understanding of their mechanical behavior. Flexure is a major mode of deformation for BHV leaflets during valve operation, inducing more complex deformation patterns within the tissue compared to tensile loads. In this study, we investigated the relation between collagen fiber preferred direction and the resulting flexural properties of native and glutaraldehyde-treated bovine pericardium. 20 turn x 4 mm strips were cut from the presorted sheets of bovine pericardium and divided into four groups: two directions of collagen fiber orientation in two groups of native and chemically treated specimens. Specimens were flexed in two different directions using a three-point bending technique (ASAIO J. 45(1999)59) and their flexural mechanical response compared. Results indicated that: (1) the relationship between the applied flexing moment and change of curvature of specimens was non-linear in both native and chemically fixed groups, (2) there were no directional differences in flexural properties when the bovine pericardium is flexed towards either the epi-pericardial or visceral surfaces in both native and chemically fixed specimens, (3) native and chemically fixed bovine pericardium were stiffer when flexed perpendicular to local preferred collagen fiber direction, and (4) chemical fixation increased the flexural rigidity of bovine pericardium. Results of this study indicate that the flexural properties of bovine pericardium are dominated by inter-fiber cross-links as opposed to the stiffness of the collagen fibers themselves. These findings can be used to guide the development of novel chemical treatment methods that seek to optimize biomechanical properties of heterograft biomaterials. (C) 2004 Elsevier Ltd. All rights reserved.