Saxton M J
Institute of Theoretical Dynamics, University of California, Davis 95616.
Biophys J. 1993 Jun;64(6):1766-80. doi: 10.1016/S0006-3495(93)81548-0.
Several laboratories have measured lateral diffusion of single particles on the cell surface, and these measurements may reveal an otherwise inaccessible level of submicroscopic organization of cell membranes. Pitfalls in the interpretation of these experiments are analyzed. Random walks in unobstructed systems show structure that could be interpreted as free diffusion, obstructed diffusion, directed motion, or trapping in finite domains. To interpret observed trajectories correctly, one must consider not only the trajectories themselves but also the probabilities of occurrence of various trajectories. Measures of the asymmetry of obstructed and unobstructed random walks are calculated, and probabilities are evaluated for random trajectories that resemble either directed motion or diffusion in a bounded region.
几个实验室已经测量了单个粒子在细胞表面的横向扩散，这些测量可能揭示细胞膜亚微观组织中一个原本难以触及的层面。本文分析了这些实验解释中的陷阱。在无障碍系统中的随机游走呈现出的结构，可能被解释为自由扩散、受阻扩散、定向运动或在有限区域内的捕获。为了正确解释观察到的轨迹，不仅必须考虑轨迹本身，还必须考虑各种轨迹出现的概率。计算了受阻和无障碍随机游走的不对称性度量，并评估了类似于定向运动或在有界区域内扩散的随机轨迹的概率。
