Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA.
Translational Tissue Engineering Center, Johns Hopkins University, Baltimore, MD, USA.
Sci Rep. 2018 Mar 22;8(1):5043. doi: 10.1038/s41598-018-23214-8.
Tissue engineering scaffolds are used in conjunction with stem cells for the treatment of various diseases. A number of factors provided by the scaffolds affect the differentiation of stem cells. Mechanical cues that are part of the natural cellular microenvironment can both accelerate the differentiation toward particular cell lineages or induce differentiation to an alternative cell fate. Among such factors, there are externally applied strains and mechanical (stiffness and relaxation time) properties of the extracellular matrix. Here, the mechanics of a fibrous-porous scaffold is studied by applying a coordinated modeling and experimental approach. A force relaxation experiment is used, and a poroelastic model associates the relaxation process with the fluid diffusion through the fibrous matrix. The model parameters, including the stiffness moduli in the directions along and across the fibers as well as fluid diffusion time, are estimated by fitting the experimental data. The time course of the applied force is then predicted for different rates of loading and scaffold porosities. The proposed approach can help in a reduction of the technological and experimental efforts to produce 3-D scaffolds for regenerative medicine as well as in a higher accuracy of the estimation of the local factors sensed by stem cells.
组织工程支架与干细胞一起用于治疗各种疾病。支架提供的许多因素会影响干细胞的分化。作为天然细胞微环境的一部分的机械线索可以加速向特定细胞谱系的分化，或诱导分化为替代的细胞命运。在这些因素中，有外部施加的应变和细胞外基质的机械（刚度和松弛时间）特性。在这里，通过应用协调的建模和实验方法来研究纤维多孔支架的力学性能。进行了力松弛实验，多孔弹性模型将松弛过程与通过纤维基质的流体扩散相关联。通过拟合实验数据来估计模型参数，包括沿纤维方向和垂直于纤维方向的刚度模量以及流体扩散时间。然后预测在不同的加载速率和支架孔隙率下施加力的时间过程。所提出的方法可以帮助减少用于再生医学的 3-D 支架的技术和实验工作，并且可以更准确地估计干细胞感知的局部因素。
