Multiscale modelling and homogenisation of fibre-reinforced hydrogels for tissue engineering
Multiscale modelling and homogenisation of fibre-reinforced hydrogels for tissue engineering
复制标题
DOI：
10.1017/s0956792518000657
复制
发表时间：
2020-02-01
影响因子：
1.9
通讯作者：
Byrne, H. M.
中科院分区：
文献类型：
--
作者：
Chen, M. J.;Kimpton, L. S.;Byrne, H. M.
组织工程旨在体外培养人工组织，以取代体内因年龄，创伤或疾病而受损的组织。最近的一种工程化人工软骨的方法涉及将细胞接种在支架内，该支架由聚合物纤维的互连3D打印晶格与铸造或打印水凝胶组合组成，并使构建体（细胞接种支架）在生物反应器中经受施加的负载。一个关键的问题是了解施加的载荷如何分布在整个结构中。为了解决这个问题，我们采用均匀化理论推导出方程的周期性，弹性多孔弹性复合材料的有效宏观尺度的材料特性。我们将纤维视为线性弹性材料，将水凝胶视为多孔弹性材料，并利用不同的长度尺度（与结构尺寸相比，纤维间间距较小）来推导宏观尺度方程，该方程控制复合材料对施加载荷的响应。这种均匀化的描述反映了复合材料的正交各向异性性质。为了验证该模型，从有限元模拟的宏观，均质化方程的解决方案相比，描述无侧限压缩的纤维增强水凝胶的实验数据。该模型是用来推导出一个范围内的纤维间距的复合材料的圆柱形结构的整体力学性能，并确定嵌入在该结构内的细胞所经历的局部力学环境。
Tissue engineering aims to grow artificial tissues in vitro to replace those in the body that have been damaged through age, trauma or disease. A recent approach to engineer artificial cartilage involves seeding cells within a scaffold consisting of an interconnected 3D-printed lattice of polymer fibres combined with a cast or printed hydrogel, and subjecting the construct (cell-seeded scaffold) to an applied load in a bioreactor. A key question is to understand how the applied load is distributed throughout the construct. To address this, we employ homogenisation theory to derive equations governing the effective macroscale material properties of a periodic, elastic-poroelastic composite. We treat the fibres as a linear elastic material and the hydrogel as a poroelastic material, and exploit the disparate length scales (small inter-fibre spacing compared with construct dimensions) to derive macroscale equations governing the response of the composite to an applied load. This homogenised description reflects the orthotropic nature of the composite. To validate the model, solutions from finite element simulations of the macroscale, homogenised equations are compared to experimental data describing the unconfined compression of the fibre-reinforced hydrogels. The model is used to derive the bulk mechanical properties of a cylindrical construct of the composite material for a range of fibre spacings and to determine the local mechanical environment experienced by cells embedded within the construct.