Jaasma Michael J, Jackson Wesley M, Keaveny Tony M
Orthopaedic Biomechanics Laboratory, Department of Mechanical Engineering, University of California, Berkeley, CA 94720-1740, USA.
Ann Biomed Eng. 2006 May;34(5):748-58. doi: 10.1007/s10439-006-9081-0. Epub 2006 Apr 8.
An understanding of whole-cell mechanical behavior can provide insight into cellular responses to mechanical loading and diseases in which such responses are altered. However, this aspect of cellular mechanical behavior has received limited attention. In this study, we used the atomic force microscope (AFM) in conjunction with several mechanical characterization methods (Hertz contact theory, an exponential equation, and a parallel-spring recruitment model) to establish a mechanically rigorous method for measuring and characterizing whole-cell mechanical behavior in the deformation range 0-500 nm. Using MC3T3-E1 osteoblasts, measurement repeatability was assessed by performing multiple loading cycles on individual cells. Despite variability in measurements, repeatability of the measurement technique was statistically confirmed. The measurement technique also proved acceptable since only 5% of the total variance across all measurements was due to variations within measurements for a single cell. The parallel-spring recruitment model, a single-parameter model, accurately described the measured nonlinear force-deformation response (R2>0.99) while providing a mechanistic explanation of whole-cell mechanical behavior. Taken together, the results should improve the capabilities of the AFM to probe whole-cell mechanical behavior. In addition, the success of the parallel-spring recruitment model provides insight into the micromechanical basis of whole-cell behavior.
对全细胞力学行为的理解能够为细胞对机械负荷的反应以及此类反应发生改变的疾病提供深入见解。然而，细胞力学行为的这一方面受到的关注有限。在本研究中，我们将原子力显微镜（AFM）与多种力学表征方法（赫兹接触理论、指数方程和平行弹簧募集模型）相结合，建立了一种在0 - 500 nm变形范围内测量和表征全细胞力学行为的力学严谨方法。使用MC3T3 - E1成骨细胞，通过对单个细胞进行多次加载循环来评估测量的重复性。尽管测量存在变异性，但测量技术的重复性得到了统计学确认。该测量技术也被证明是可接受的，因为在所有测量中，总方差中只有5%是由于单个细胞测量内的变化所致。单参数的平行弹簧募集模型准确地描述了测量到的非线性力 - 变形响应（R2>0.99），同时为全细胞力学行为提供了一种机理解释。综上所述，这些结果应能提高AFM探测全细胞力学行为的能力。此外，平行弹簧募集模型的成功为全细胞行为的微观力学基础提供了深入见解。
