Kusters Remy, Storm Cornelis
Department of Applied Physics and Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, NL-5600 MB Eindhoven, The Netherlands.
Phys Rev E Stat Nonlin Soft Matter Phys. 2014 Mar;89(3):032723. doi: 10.1103/PhysRevE.89.032723. Epub 2014 Mar 31.
Diffusive processes on nonplanar substrates are deeply relevant for cellular function and transport and increasingly used to probe and characterize the behavior of proteins in membranes. We present analytical and numerical analyses of in-plane diffusion of discrete particles on curved geometries reflecting various generic motifs in biology and explore, in particular, the effect that the shape of the substrate has on the characteristic time scales of diffusive processes. To this end, we consider both collective measures (the relaxation of concentration profiles towards equilibrium) and single-particle measures (escape rates and first passage times of individual diffusing molecules): the first relevant for the correct interpretation of FRAP experiments in curved environments; the second, for single-particle tracking probes. Each of these measures is sensitively affected by the morphology of the substrate, and we find that the exit rate out of a domain is not uniquely set by the size of its boundary, illustrating the general principle we reveal: By varying the shape of a substrate, Nature can control the diffusive time scales in a microenvironment without changing the bare substrate properties.
非平面基底上的扩散过程与细胞功能和运输密切相关，并且越来越多地用于探测和表征膜中蛋白质的行为。我们对反映生物学中各种通用基序的弯曲几何形状上离散粒子的平面内扩散进行了分析和数值分析，特别探讨了基底形状对扩散过程特征时间尺度的影响。为此，我们考虑了集体测量（浓度分布向平衡的弛豫）和单粒子测量（单个扩散分子的逃逸率和首次通过时间）：前者对于在弯曲环境中正确解释荧光恢复后漂白（FRAP）实验至关重要；后者对于单粒子跟踪探针至关重要。这些测量中的每一个都受到基底形态的敏感影响，并且我们发现从一个区域的退出速率并非由其边界大小唯一确定，这说明了我们所揭示的一般原理：通过改变基底的形状，自然可以在不改变裸基底性质的情况下控制微环境中的扩散时间尺度。
