Effect of Dynamic Loading on the Transport of Solutes into Agarose Hydrogels
Effect of Dynamic Loading on the Transport of Solutes into Agarose Hydrogels
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DOI：
10.1016/j.bpj.2009.05.047
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发表时间：
2009-08-19
影响因子：
3.4
通讯作者：
Ateshian, Gerard A.
中科院分区：
文献类型：
--
作者：
Chahine, Nadeen O.;Albro, Michael B.;Ateshian, Gerard A.
在功能性组织工程中，动态加载的应用已被证明可以改善软骨细胞种子琼脂糖水凝胶的力学性能，而不是卸载自由肿胀对照。本研究的目的是确定动态负荷对组织工程结构中营养物质运输的影响。为了消除混杂效应，如细胞负载磁盘中的营养消耗，本研究使用无细胞琼脂糖磁盘和葡聚糖在磷酸盐缓冲盐水（3和70 kDa）中的模型系统，研究了由于负载引起的溶质运输的响应。对葡聚糖在琼脂糖中的被动扩散反应的研究证实了菲克扩散定律在描述葡聚糖行为方面的适用性。在静态载荷下，与自由膨胀相比，压缩应变的应用减少了70 kDa葡聚糖可用的总间隙体积。与静态加载相比，动态加载显著提高了琼脂糖圆盘对溶质的吸收速率。此外，动态负载下葡聚糖的稳态浓度明显大于静态负载下的稳态浓度，因为葡聚糖的分子质量较大（70 kDa）。这一实验发现证实了最近的理论预测，即多孔组织的机械泵送可能会主动将溶质输送到磁盘中，而不顾它们的浓度梯度。本研究的结果支持了一个假设，即在存在大分子量生长因子的情况下，应用动态负载可能会导致组织生长的机械和化学刺激环境。
In functional tissue engineering, the application of dynamic loading has been shown to improve the mechanical properties of chondrocyte-seeded agarose hydrogels relative to unloaded free swelling controls. The goal of this study is to determine the effect of dynamic loading on the transport of nutrients in tissue-engineered constructs. To eliminate confounding effects, such as nutrient consumption in cell-laden disks, this study examines the response of solute transport due to loading using a model system of acellular agarose disks and dextran in phosphate-buffered saline (3 and 70 kDa). An examination of the passive diffusion response of dextran in agarose confirms the applicability of Fick's law of diffusion in describing the behavior of dextran. Under static loading, the application of compressive strain decreased the total interstitial volume available for the 70 kDa dextran, compared to free swelling. Dynamic loading significantly enhanced the rate of solute uptake into agarose disks, relative to static loading. Moreover, the steady-state concentration under dynamic loading was found to be significantly greater than under static loading, for larger-molecular-mass dextran (70 kDa). This experimental finding confirms recent theoretical predictions that mechanical pumping of a porous tissue may actively transport solutes into the disk against their concentration gradient. The results of this study support the hypothesis that the application of dynamic loading in the presence of growth factors of large molecular weight may result in both a mechanically and chemically stimulating environment for tissue growth.