Wiggins C H, Riveline D, Ott A, Goldstein R E
Department of Physics, Princeton University, New Jersey 08544, USA.
Biophys J. 1998 Feb;74(2 Pt 1):1043-60. doi: 10.1016/S0006-3495(98)74029-9.
We present an analysis of the planar motion of single semiflexible filaments subject to viscous drag or point forcing. These are the relevant forces in dynamic experiments designed to measure biopolymer bending moduli. By analogy with the "Stokes problems" in hydrodynamics (motion of a viscous fluid induced by that of a wall bounding the fluid), we consider the motion of a polymer, one end of which is moved in an impulsive or oscillatory way. Analytical solutions for the time-dependent shapes of such moving polymers are obtained within an analysis applicable to small-amplitude deformations. In the case of oscillatory driving, particular attention is paid to a characteristic length determined by the frequency of oscillation, the polymer persistence length, and the viscous drag coefficient. Experiments on actin filaments manipulated with optical traps confirm the scaling law predicted by the analysis and provide a new technique for measuring the elastic bending modulus. Exploiting this model, we also present a reanalysis of several published experiments on microtubules.
我们对受粘性阻力或点力作用的单个半柔性细丝的平面运动进行了分析。这些是旨在测量生物聚合物弯曲模量的动态实验中的相关力。类似于流体动力学中的“斯托克斯问题”（由界定流体的壁的运动引起的粘性流体的运动），我们考虑聚合物的运动，其一端以脉冲或振荡方式移动。在适用于小振幅变形的分析中，获得了此类移动聚合物随时间变化形状的解析解。在振荡驱动的情况下，特别关注由振荡频率、聚合物持久长度和粘性阻力系数确定的特征长度。用光镊操纵肌动蛋白丝的实验证实了分析预测的标度律，并提供了一种测量弹性弯曲模量的新技术。利用这个模型，我们还对一些已发表的关于微管的实验进行了重新分析。
