The Role of Buckling Instabilities in the Global and Local Mechanical Response in Porous Collagen Scaffolds
The Role of Buckling Instabilities in the Global and Local Mechanical Response in Porous Collagen Scaffolds
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DOI：
10.1007/s11340-022-00853-7
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发表时间：
2022-06
影响因子：
2.4
通讯作者：
B. Kim;J. Middendorf;N. Diamantides;C. Dugopolski;S. Kennedy;E. Blahut;I. Cohen;N. Bouklas;L. Bonassar
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文献类型：
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作者：
B. Kim;J. Middendorf;N. Diamantides;C. Dugopolski;S. Kennedy;E. Blahut;I. Cohen;N. Bouklas;L. Bonassar
背景多孔聚合物支架通常用于再生医学和组织工程治疗中的结构组织的修复和再生，这些结构组织需要足够的机械完整性来抵抗组织长入之前的负载。对具有蜂窝和海绵结构的两种类型的多孔胶原支架进行了尺度力学分析。使用受限压缩测试来评估支架的整体非线性机械响应。此外，我们进行了共焦应变映射结合数字图像相关（DIC）可视化局部机械不稳定性和比较支架architecture.ResultsThe的全局响应的支架架构之间的局部应变分布遵循的模式特征的细胞固体，与线性区域，高原区域，和致密化区域。宏观尺度的非线性响应对应于局部尺度的不稳定性，如突跳屈曲。在局部规模上，建筑物的压缩响应在很大程度上取决于建筑类型。具有蜂窝结构的支架在整个支架深度上经历了单峰应变分布。相比之下，海绵架构的支架往往崩溃在boundaries.ConclusionsWe表明，支架结构之间的机械响应的差异主要是在微观尺度上检测到的，这源于孔隙结构的差异。因此，像共焦应变映射结合DIC这样的工具对于设计和优化多孔材料的结构至关重要。观察多孔材料中的局部不稳定性不仅对于调节机械响应，而且对于控制影响细胞和组织行为的机械事件是重要的。
BackgroundPorous polymer scaffolds are commonly used for regenerative medicine and tissue-engineered therapies in the repair and regeneration of structural tissues which require sufficient mechanical integrity to resist loading prior to tissue ingrowth.ObjectiveInvestigate the connection between scaffold architecture and mechanical response of collagen scaffolds used in human tissue-engineered cartilage.MethodsWe performed multi-scale mechanical analysis on two types of porous collagen scaffolds with honeycomb and sponge architectures. Confined compression testing was used to assess global non-linear mechanical response of scaffolds. Additionally, we performed confocal strain mapping combined with digital image correlation (DIC) to visualize local mechanical instabilities and compared local strain distributions between scaffold architectures.ResultsThe global response of both scaffold architectures followed a pattern characteristic of cellular solids, with a linear region, a plateau region, and a densification region. Macro-scale non-linear responses corresponded to local-scale instabilities such as snap-through buckling. On the local-scale, a construct’s compressive response depended heavily on the architecture type. Scaffolds with honeycomb architecture experienced a unimodal strain distribution throughout the scaffold depth. In contrast, scaffolds with sponge architecture tended to collapse at the boundaries.ConclusionsWe demonstrated that differences in mechanical response between scaffold architectures were detected primarily at the micro-scale which stems from the disparity in pore architecture. As such, tools like confocal strain mapping combined with DIC are critical for designing and optimizing architectures for porous materials. Observing local instabilities in porous materials is important not only for tuning mechanical response, but also for controlling mechanical events that influence cellular and tissue behavior.