Institute for Theoretical Physics, Heidelberg University, Philosophenweg 19, 69120 Heidelberg, Germany.
BioQuant, Heidelberg University, Im Neuenheimer Feld 267, 69120 Heidelberg, Germany.
Soft Matter. 2024 Jun 5;20(22):4488-4503. doi: 10.1039/d4sm00345d.
The nucleus of eukaryotic cells typically makes up around 30% of the cell volume and has significantly different mechanics, which can make it effectively up to ten times stiffer than the surrounding cytoplasm. Therefore it is an important element for cell mechanics, but a quantitative understanding of its mechanical role during whole cell dynamics is largely missing. Here we demonstrate that elastic phase fields can be used to describe dynamical cell processes in adhesive or confining environments in which the nucleus acts as a stiff inclusion in an elastic cytoplasm. We first introduce and verify our computational method and then study several prevalent cell-mechanical measurement methods. For cells on adhesive patterns, we find that nuclear stress is shielded by the adhesive pattern. For cell compression between two parallel plates, we obtain force-compression curves that allow us to extract an effective modulus for the cell-nucleus composite. For micropipette aspiration, the effect of the nucleus on the effective modulus is found to be much weaker, highlighting the complicated interplay between extracellular geometry and cell mechanics that is captured by our approach. We also show that our phase field approach can be used to investigate the effects of Kelvin-Voigt-type viscoelasticity and cortical tension.
真核细胞的核通常占细胞体积的 30%左右，其力学性质有显著差异，核的硬度可比周围细胞质高 10 倍左右。因此，核是细胞力学的一个重要组成部分，但对于整个细胞动力学过程中核的机械作用，目前还缺乏定量的理解。在这里，我们证明了弹性相场可以用来描述在粘性或约束环境中的动态细胞过程，其中核作为弹性细胞质中的硬夹杂。我们首先介绍并验证了我们的计算方法，然后研究了几种常见的细胞力学测量方法。对于在黏附图案上的细胞，我们发现核的应力被黏附图案屏蔽了。对于两个平行平板之间的细胞压缩，我们得到了力-压缩曲线，从中可以提取出细胞-核复合材料的有效模量。对于微吸管抽吸，发现核对有效模量的影响要弱得多，这突出了我们的方法所捕捉到的细胞外几何形状和细胞力学之间复杂的相互作用。我们还表明，我们的相场方法可以用来研究 Kelvin-Voigt 型粘弹性和皮质张力的影响。
