School of Electrical and Communication Engineering, University of Electronic Science and Technology of China, Chengdu, Sichuan, China.
Department of Mechanical Engineering, Iowa State University, Ames, IA, USA.
Biomech Model Mechanobiol. 2017 Dec;16(6):1857-1868. doi: 10.1007/s10237-017-0924-4. Epub 2017 Jun 8.
Study of the dynamic evolutions of cell viscoelasticity is important as during cell activities such as cell metastasis and invasion, the rheological behaviors of the cells also change dynamically, reflecting the biophysical and biochemical connections between the outer cortex and the intracellular structures. Although the time variations of the static modulus of cells have been investigated, few studies have been reported on the dynamic variations of the frequency-dependent viscoelasticity of cells. Measuring and monitoring such dynamic evolutions of cells at nanoscale can be challenging as the measurement needs to meet two objectives inherently contradictory to each other-the measurement must be broadband (to cover a large frequency spectrum) but also rapid (to capture the time-elapsed changes). In this study, we exploited a recently developed control-based nanomechanical protocol of atomic force microscope to monitor in real time the dynamic evolutions of the viscoelasticity of live human prostate cancer cells (PC-3 cells) and study its dependence on myosin activities. We found that the viscoelasticity of PC-3 cells, followed the power law, and oscillated at a period of about 200 s. Both the amplitude and the frequency of the oscillation strongly depended on the intracellular calcium and blebbistatin-sensitive motor proteins.
研究细胞黏弹性的动态变化非常重要，因为在细胞活动（如细胞转移和入侵）期间，细胞的流变行为也会动态变化，反映了细胞外皮质和细胞内结构之间的生物物理和生化联系。尽管已经研究了细胞静态模量的时间变化，但关于细胞频率相关黏弹性的动态变化的研究很少。在纳米尺度上测量和监测细胞的这种动态演变具有挑战性，因为测量需要满足两个内在相互矛盾的目标——测量必须是宽带的（以覆盖大的频谱），但也要快速（以捕捉随时间流逝的变化）。在这项研究中，我们利用原子力显微镜最近开发的基于控制的纳米力学协议实时监测活人类前列腺癌细胞（PC-3 细胞）黏弹性的动态演变，并研究其对肌球蛋白活性的依赖性。我们发现，PC-3 细胞的黏弹性遵循幂律，并以约 200 s 的周期振荡。振荡的幅度和频率都强烈依赖于细胞内钙和 blebbistatin 敏感的运动蛋白。
