Instituto de Ciencia de Materiales de Madrid, CSIC, c/ Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain.
Nanoscale. 2020 Apr 28;12(16):9133-9143. doi: 10.1039/c9nr10316c. Epub 2020 Apr 15.
Mechanobiology aims to establish functional relationships between the mechanical state of a living a cell and its physiology. The acquisition of force-distance curves with an AFM is by far the dominant method to characterize the nanomechanical properties of living cells. However, theoretical simulations have shown that the contact mechanics models used to determine the Young's modulus from a force-distance curve could be off by a factor 5 from its expected value. The semi-quantitative character arises from the lack of a theory that integrates the AFM data, a realistic viscoelastic model of a cell and its finite-thickness. Here, we develop a method to determine the mechanical response of a cell from a force-distance curve. The method incorporates bottom-effect corrections, a power-law rheology model and the deformation history of the cell. It transforms the experimental data into viscoelastic parameters of the cell as a function of the indentation frequency. The quantitative agreement obtained between the experiments performed on living fibroblast cells and the analytical theory supports the use of force-distance curves to measure the nanorheological properties of cells.
力学生物学旨在建立活细胞的机械状态与其生理学之间的功能关系。迄今为止，使用原子力显微镜（AFM）获取力-距离曲线是表征活细胞纳米力学特性的主要方法。然而，理论模拟表明，用于从力-距离曲线确定杨氏模量的接触力学模型可能与其预期值相差 5 倍。这种半定量的特性源于缺乏一种理论，该理论可以整合 AFM 数据、细胞的现实粘弹性模型及其有限厚度。在这里，我们开发了一种从力-距离曲线确定细胞力学响应的方法。该方法包含底部效应校正、幂律流变学模型和细胞的变形历史。它将实验数据转换为细胞的粘弹性参数，作为压入频率的函数。在对活成纤维细胞进行的实验与分析理论之间获得的定量一致性支持使用力-距离曲线来测量细胞的纳米流变特性。
