IMDEA Materials Institute, C/ Profesor Aranguren s/n, 28040 Madrid, Spain.
Acta Biomater. 2012 Sep;8(9):3360-71. doi: 10.1016/j.actbio.2012.04.039. Epub 2012 May 2.
Traumatic brain injuries have recently been put under the spotlight as one of the most important causes of accidental brain dysfunctions. Significant experimental and modeling efforts are thus underway to study the associated biological, mechanical and physical mechanisms. In the field of cell mechanics, progress is also being made at the experimental and modeling levels to better characterize many of the cell functions, including differentiation, growth, migration and death. The work presented here aims to bridge both efforts by proposing a continuum model of a neuronal cell submitted to blast loading. In this approach, the cytoplasm, nucleus and membrane (plus cortex) are differentiated in a representative cell geometry, and different suitable material constitutive models are chosen for each one. The material parameters are calibrated against published experimental work on cell nanoindentation at multiple rates. The final cell model is ultimately subjected to blast loading within a complete computational framework of fluid-structure interaction. The results are compared to the nanoindentation simulation, and the specific effects of the blast wave on the pressure and shear levels at the interfaces are identified. As a conclusion, the presented model successfully captures some of the intrinsic intracellular phenomena occurring during the cellular deformation under blast loading that potentially lead to cell damage. It suggests, more particularly, that the localization of damage at the nucleus membrane is similar to what has already been observed at the overall cell membrane. This degree of damage is additionally predicted to be worsened by a longer blast positive phase duration. In conclusion, the proposed model ultimately provides a new three-dimensional computational tool to evaluate intracellular damage during blast loading.
创伤性脑损伤最近成为意外脑功能障碍的最重要原因之一，受到了广泛关注。因此，人们正在进行大量的实验和建模工作，以研究相关的生物、机械和物理机制。在细胞力学领域，实验和建模方面也取得了进展，以更好地描述许多细胞功能，包括分化、生长、迁移和死亡。本工作旨在通过提出一种受爆炸载荷作用的神经元细胞的连续体模型来弥合这两项工作的差距。在这种方法中，细胞质、细胞核和细胞膜（加皮层）在代表性的细胞几何形状中得到区分，并为每一个部分选择了不同的合适材料本构模型。材料参数根据细胞纳米压痕在多个速率下的发表实验工作进行校准。最终的细胞模型最终在完整的流固耦合计算框架内受到爆炸载荷的作用。将结果与纳米压痕模拟进行比较，并确定了爆炸波在界面处的压力和剪切水平的特定影响。作为结论，所提出的模型成功地捕捉到了细胞在爆炸载荷下变形过程中发生的一些内在的细胞内现象，这些现象可能导致细胞损伤。特别是，损伤定位于核膜的位置与已经在整个细胞膜上观察到的位置相似。这种损伤程度预计会因爆炸正相持续时间更长而恶化。总之，所提出的模型最终提供了一种新的三维计算工具，用于评估爆炸载荷作用下的细胞内损伤。
