Jones Anthony C, Arns Christoph H, Hutmacher Dietmar W, Milthorpe Bruce K, Sheppard Adrian P, Knackstedt Mark A
Department of Applied Mathematics, Research School of Physical Sciences and Engineering, Australian National University, Canberra ACT 0200, Australia.
Biomaterials. 2009 Mar;30(7):1440-51. doi: 10.1016/j.biomaterials.2008.10.056. Epub 2008 Dec 16.
In the design of tissue engineering scaffolds, design parameters including pore size, shape and interconnectivity, mechanical properties and transport properties should be optimized to maximize successful inducement of bone ingrowth. In this paper we describe a 3D micro-CT and pore partitioning study to derive pore scale parameters including pore radius distribution, accessible radius, throat radius, and connectivity over the pore space of the tissue engineered constructs. These pore scale descriptors are correlated to bone ingrowth into the scaffolds. Quantitative and visual comparisons show a strong correlation between the local accessible pore radius and bone ingrowth; for well connected samples a cutoff accessible pore radius of approximately 100 microM is observed for ingrowth. The elastic properties of different types of scaffolds are simulated and can be described by standard cellular solids theory: (E/E(0))=(rho/rho(s))(n). Hydraulic conductance and diffusive properties are calculated; results are consistent with the concept of a threshold conductance for bone ingrowth. Simple simulations of local flow velocity and local shear stress show no correlation to in vivo bone ingrowth patterns. These results demonstrate a potential for 3D imaging and analysis to define relevant pore scale morphological and physical properties within scaffolds and to provide evidence for correlations between pore scale descriptors, physical properties and bone ingrowth.
在组织工程支架的设计中，应优化包括孔径、形状和连通性、力学性能以及传输性能在内的设计参数，以最大程度地成功诱导骨长入。在本文中，我们描述了一项三维显微CT和孔隙划分研究，以得出孔隙尺度参数，包括孔隙半径分布、可及半径、喉道半径以及组织工程构建体孔隙空间的连通性。这些孔隙尺度描述符与支架内的骨长入相关。定量和可视化比较表明，局部可及孔隙半径与骨长入之间存在很强的相关性；对于连通性良好的样品，观察到骨长入的可及孔隙半径临界值约为100微米。模拟了不同类型支架的弹性性能，可用标准多孔固体理论描述：(E/E(0))=(rho/rho(s))(n)。计算了水力传导率和扩散性能；结果与骨长入的阈值传导概念一致。局部流速和局部剪切应力的简单模拟显示与体内骨长入模式无关。这些结果表明，三维成像和分析有潜力定义支架内相关的孔隙尺度形态和物理性能，并为孔隙尺度描述符、物理性能和骨长入之间的相关性提供证据。
