Matrix deposition modulates the viscoelastic shear properties of hydrogel-based cartilage grafts.
Matrix deposition modulates the viscoelastic shear properties of hydrogel-based cartilage grafts.
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DOI：
10.1089/ten.tea.2010.0379
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发表时间：
2011-01
影响因子：
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通讯作者：
L. Wan;Jie Jiang;Diana E Miller;X. Guo;V. Mow;Helen H. Lu
中科院分区：
文献类型：
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作者：
L. Wan;Jie Jiang;Diana E Miller;X. Guo;V. Mow;Helen H. Lu
基于水凝胶的支架如藻酸盐已被广泛研究用于软骨组织工程，主要是由于其生物相容性、环境胶凝条件和支持软骨细胞表型的能力。虽然已经确定关节软骨的粘弹性响应对于关节和承重是必不可少的，但是基于水凝胶的软骨支架的时间依赖性机械性能尚未被广泛研究。因此，本研究的目的是表征软骨细胞负载藻酸盐支架的固有粘弹性剪切特性，并确定接种密度和培养时间对这些特性的影响。具体来说，在扭转剪切下测量了这些工程化软骨移植物的粘弹特性（平衡和动态剪切模量以及动态相移角）。此外，使用准线性粘弹性（QLV）理论模拟了基于海藻酸盐的软骨支架的快速斜坡-阶梯剪切应力松弛。发现支架刚度随培养时间和细胞密度增加，而粘度不随细胞密度显著变化（30对60百万/mL）。与天然软骨相似，工程支架在纯剪切下的能量耗散与糖胺聚糖含量高度相关。相反，胶原蛋白含量与支架剪切模量，特别是准线性粘弹性模型预测的瞬时剪切模量没有很强的相关性。本研究的结果为工程化软骨的结构与功能的关系以及软骨修复的功能性移植物的设计提供了新的见解。
Hydrogel-based scaffolds such as alginate have been extensively investigated for cartilage tissue engineering, largely due to their biocompatibility, ambient gelling conditions, and the ability to support chondrocyte phenotype. While it is well established that the viscoelastic response of articular cartilage is essential for articulation and load bearing, the time-dependent mechanical properties of hydrogel-based cartilage scaffolds have not been extensively studied. Therefore, the objective of this study was to characterize the intrinsic viscoelastic shear properties of chondrocyte-laden alginate scaffolds and determine the effects of seeding density and culturing time on these properties. Specifically, the viscoelastic properties (equilibrium and dynamic shear moduli and dynamic phase shift angle) of these engineered cartilage grafts were measured under torsional shear. In addition, the rapid ramp-step shear stress relaxation of the alginate-based cartilage scaffolds was modeled using the quasi-linear viscoelastic (QLV) theory. It was found that scaffold stiffness increased with both culturing time and cell density, whereas viscosity did not change significantly with cell density (30 vs. 60 million/mL). Similar to native cartilage, the energy dissipation of engineered scaffolds under pure shear is highly correlated to the glycosaminoglycan content. In contrast, collagen content was not strongly correlated to scaffold shear modulus, especially the instantaneous shear modulus predicted by the quasi-linear viscoelastic model. The findings of this study provide new insights into the structure-function relationship of engineered cartilage and design of functional grafts for cartilage repair.