Hang Jiu-Tao, Xu Guang-Kui, Gao Huajian
Laboratory for Multiscale Mechanics and Medical Science, Department of Engineering Mechanics, SVL, School of Aerospace Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
School of Mechanical and Aerospace Engineering, College of Engineering, Nanyang Technological University, Singapore 639798, Singapore.
Sci Adv. 2022 May 6;8(18):eabn6093. doi: 10.1126/sciadv.abn6093.
Living cells are active viscoelastic materials exhibiting diverse mechanical behaviors at different time scales. However, dynamical rheological characteristics of cells in frequency range spanning many orders of magnitude, especially in high frequencies, remain poorly understood. Here, we show that a self-similar hierarchical model can capture cell's power-law rheological characteristics in different frequency scales. In low-frequency scales, the storage and loss moduli exhibit a weak power-law dependence on frequency with same exponent. In high-frequency scales, the storage modulus becomes a constant, while the loss modulus shows a power-law dependence on frequency with an exponent of 1.0. The transition between low- and high-frequency scales is defined by a transition frequency based on cell's mechanical parameters. The cytoskeletal differences of different cell types or states can be characterized by changes in mechanical parameters in the model. This study provides valuable insights into potentially using mechanics-based markers for cell classification and cancer diagnosis.
活细胞是活跃的粘弹性材料，在不同时间尺度上表现出多样的力学行为。然而，细胞在跨越多个数量级的频率范围内，尤其是在高频下的动态流变特性仍知之甚少。在此，我们表明一个自相似层次模型能够捕捉细胞在不同频率尺度下的幂律流变特性。在低频尺度下，储能模量和损耗模量对频率呈现出弱幂律依赖关系，且指数相同。在高频尺度下，储能模量变为常数，而损耗模量对频率呈现幂律依赖关系，指数为1.0。低频和高频尺度之间的转变由基于细胞力学参数的转变频率定义。不同细胞类型或状态的细胞骨架差异可通过模型中力学参数的变化来表征。本研究为潜在地使用基于力学的标志物进行细胞分类和癌症诊断提供了有价值的见解。
