Combining AFM and Acoustic Probes to Reveal Changes in the Elastic Stiffness Tensor of Living Cells
Combining AFM and Acoustic Probes to Reveal Changes in the Elastic Stiffness Tensor of Living Cells
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DOI：
10.1016/j.bpj.2014.07.073
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发表时间：
2014-10-07
影响因子：
3.4
通讯作者：
Derby, Brian
中科院分区：
文献类型：
--
作者：
Nijenhuis, Nadja;Zhao, Xuegen;Derby, Brian
了解细胞的弹性刚度如何影响其与环境的通信，对于理解健康和疾病中的组织完整性具有根本的重要性。对于刚度测量，通常引用单个参数量，例如，杨氏模量，而不是弹性理论所要求的刚度张量的两项中的最小值。在这项研究中，我们使用两个独立的方法（声学显微镜和原子力显微镜纳米压痕）来表征细胞的弹性特性，从而确定两个独立的弹性常数。这使我们能够详细探索细胞的机械特性如何响应已知调节细胞细胞骨架的信号通路而变化。特别是，我们表明，改变拉伸的肌动蛋白丝在NIH 3T3细胞有很强的影响细胞的剪切模量，但其体积模量不变。相反，改变肌动蛋白丝的聚合状态以类似的方式影响体积模量和剪切模量。此外，我们可以使用这些数据来直接确定细胞的泊松比，并表明在所有研究的情况下，它都小于，但非常接近，0.5的值。
Knowledge of how the elastic stiffness of a cell affects its communication with its environment is of fundamental importance for the understanding of tissue integrity in health and disease. For stiffness measurements, it has been customary to quote a single parameter quantity, e.g., Young's modulus, rather than the minimum of two terms of the stiffness tensor required by elasticity theory. In this study, we use two independent methods (acoustic microscopy and atomic force microscopy nano-indentation) to characterize the elastic properties of a cell and thus determine two independent elastic constants. This allows us to explore in detail how the mechanical properties of cells change in response to signaling pathways that are known to regulate the cell's cytoskeleton. In particular, we demonstrate that altering the tensioning of actin filaments in NIH3T3 cells has a strong influence on the cell's shear modulus but leaves its bulk modulus unchanged. In contrast, altering the polymerization state of actin filaments influences bulk and shear modulus in a similar manner. In addition, we can use the data to directly determine the Poisson ratio of a cell and show that in all cases studied, it is less than, but very close to, 0.5 in value.