Wilson Zachary D, Kohles Sean S
Reparative Bioengineering Laboratory, Department of Mechanical and Materials Engineering, Portland State University, Portland, OR 97207.
J Nanotechnol Eng Med. 2010 May 1;1(2):21005. doi: 10.1115/1.4001309.
Investigations in cellular and molecular engineering have explored the impact of nanotechnology and the potential for monitoring and control of human diseases. In a recent analysis, the dynamic fluid-induced stresses were characterized during microfluidic applications of an instrument with nanometer and picoNewton resolution as developed for single-cell biomechanics (Kohles, S. S., Nève, N., Zimmerman, J. D., and Tretheway, D. C., 2009, "Stress Analysis of Microfluidic Environments Designed for Isolated Biological Cell Investigations," ASME J. Biomech. Eng., 131(12), p. 121006). The results described the limited stress levels available in laminar, creeping-flow environments, as well as the qualitative cellular strain response to such stress applications. In this study, we present a two-dimensional computational model exploring the physical application of normal and shear stress profiles (with 0.1, 1.0, and 10.0 Pa peak amplitudes) potentially available within uniform and extensional flow states. The corresponding cellular strains and strain patterns were determined within cells modeled with healthy and diseased mechanical properties (5.0-0.1 kPa moduli, respectively). Strain energy density results integrated over the volume of the planar section indicated a strong mechanical sensitivity involving cells with disease-like properties. In addition, ex vivo microfluidic environments creating in vivo stress states would require freestream flow velocities of 2-7 mm/s. Knowledge of the nanomechanical stresses-strains necessary to illicit a biologic response in the cytoskeleton and cellular membrane will ultimately lead to refined mechanotransduction relationships.
细胞与分子工程领域的研究探索了纳米技术的影响以及监测和控制人类疾病的潜力。在最近的一项分析中，对一种为单细胞生物力学开发的具有纳米和皮牛顿分辨率的仪器在微流体应用过程中的动态流体诱导应力进行了表征（科尔斯，S.S.，内夫，N.，齐默尔曼，J.D.，和特雷思韦，D.C.，2009年，“用于孤立生物细胞研究的微流体环境的应力分析”，美国机械工程师协会《生物医学工程杂志》，131(12)，第121006页）。结果描述了层流、蠕动流环境中可用的有限应力水平，以及细胞对这种应力应用的定性应变响应。在本研究中，我们提出了一个二维计算模型，探索在均匀流和伸展流状态下可能存在的法向和剪应力分布（峰值幅度分别为0.1、1.0和10.0帕斯卡）的物理应用。在具有健康和患病力学特性（模量分别为5.0 - 0.1千帕斯卡）的细胞模型中确定了相应的细胞应变和应变模式。在平面截面体积上积分得到的应变能密度结果表明，具有疾病样特性的细胞具有很强的力学敏感性。此外，创造体内应力状态的体外微流体环境需要2 - 7毫米/秒的自由流速度。了解在细胞骨架和细胞膜中引发生物反应所需的纳米机械应力 - 应变最终将导致更精确的机械转导关系。
