Manzano Sara, Armengol Monica, J Price Andrew, A Hulley Philippa, S Gill Harinderjit, Doblaré Manuel, Hamdy Doweidar Mohamed
Mechanical Engineering Department, School of Engineering and Architecture (EINA), University of Zaragoza, Spain.
Aragón Institute of Engineering Research (I3A), University of Zaragoza, Spain.
PLoS One. 2016 Jun 21;11(6):e0157967. doi: 10.1371/journal.pone.0157967. eCollection 2016.
Articular cartilage exhibits complex mechano-electrochemical behaviour due to its anisotropy, inhomogeneity and material non-linearity. In this work, the thickness and radial dependence of cartilage properties are incorporated into a 3D mechano-electrochemical model to explore the relevance of heterogeneity in the behaviour of the tissue. The model considers four essential phenomena: (i) osmotic pressure, (ii) convective and diffusive processes, (iii) chemical expansion and (iv) three-dimensional through-the-thickness heterogeneity of the tissue. The need to consider heterogeneity in computational simulations of cartilage behaviour and in manufacturing biomaterials mimicking this tissue is discussed. To this end, healthy tibial plateaus from pigs were mechanically and biochemically tested in-vitro. Heterogeneous properties were included in the mechano-electrochemical computational model to simulate tissue swelling. The simulation results demonstrated that swelling of the heterogeneous samples was significantly lower than swelling under homogeneous and isotropic conditions. Furthermore, there was a significant reduction in the flux of water and ions in the former samples. In conclusion, the computational model presented here can be considered as a valuable tool for predicting how the variation of cartilage properties affects its behaviour, opening up possibilities for exploring the requirements of cartilage-mimicking biomaterials for tissue engineering. Besides, the model also allows the establishment of behavioural patterns of swelling and of water and ion fluxes in articular cartilage.
关节软骨由于其各向异性、不均匀性和材料非线性而表现出复杂的机械 - 电化学行为。在这项工作中，软骨特性的厚度和径向依赖性被纳入一个三维机械 - 电化学模型，以探究组织行为中异质性的相关性。该模型考虑了四个基本现象：（i）渗透压，（ii）对流和扩散过程，（iii）化学膨胀，以及（iv）组织的三维厚度方向异质性。讨论了在软骨行为的计算模拟以及制造模仿该组织的生物材料时考虑异质性的必要性。为此，对猪的健康胫骨平台进行了体外力学和生化测试。在机械 - 电化学计算模型中纳入了非均匀特性以模拟组织肿胀。模拟结果表明，非均匀样品的肿胀明显低于均匀和各向同性条件下的肿胀。此外，前一种样品中的水和离子通量显著降低。总之，这里提出的计算模型可被视为预测软骨特性变化如何影响其行为的有价值工具，为探索组织工程中模仿软骨的生物材料的要求开辟了可能性。此外，该模型还允许建立关节软骨肿胀以及水和离子通量的行为模式。
