Materials Science Factory, Instituto de Ciencia de Materiales de Madrid, CSIC, c/Sor Juana Ines de la Cruz 3, 28049 Madrid, Spain.
Nanoscale. 2018 Nov 1;10(42):19799-19809. doi: 10.1039/c8nr05899g.
Understanding the relationship between the mechanical properties of living cells and physiology is a central issue in mechanobiology. Mechanical properties are used as fingerprints of the pathological state of a single cell. The force exerted on a cell is influenced by the stiffness of the solid support needed to culture it. This effect is a consequence of the cell's boundary conditions. It causes a cell to appear with mechanical properties different from their real values. Here we develop a bottom effect viscoelastic theory to determine the viscoelastic response of a cell. The theory transforms a force-distance curve into the cell's Young's modulus, loss modulus, relaxation time or viscosity coefficient with independence of the stiffness of the rigid support. The theory predicts that, for a given indentation, the force exerted on the cell's periphery will be larger than on a perinuclear region. Results based on the use of semi-infinite contact mechanics models introduce large numerical errors in the determination of the mechanical properties. Finite element simulations confirm the theory and define its range of applicability.
理解活细胞的力学特性与生理学之间的关系是力学生物学的核心问题。力学特性可用作单细胞病理状态的指纹。作用于细胞的力受到培养它所需的刚性支撑的硬度的影响。这种效应是细胞边界条件的结果。它导致细胞表现出与其真实值不同的力学特性。在这里，我们开发了一种底部效应粘弹性理论来确定细胞的粘弹性响应。该理论将力-距离曲线转换为细胞的杨氏模量、损耗模量、松弛时间或粘度系数，而与刚性支撑的硬度无关。该理论预测，对于给定的压痕，作用于细胞外围的力将大于核周区域的力。基于使用半无限接触力学模型的结果在确定力学特性时会引入较大的数值误差。有限元模拟证实了该理论，并定义了其适用范围。
