Anomalous dynamics of intruders in a crowded environment of mobile obstacles
Tatjana Sentjabrskaja, Emanuela Zaccarelli, Cristiano De Michele, Francesco Sciortino, Piero Tartaglia, Thomas Voigtmann, Stefan U. Egelhaaf, Marco Laurati
Many natural and industrial processes rely on constrained transport, such as proteins moving through cells, particles confined in nanocomposite materials or gels, individuals in highly dense collec- tives and vehicular traffic conditions. These are examples of motion through crowded environments, in which the host matrix may retain some glass-like dynamics. Here we investigate constrained transport in a colloidal model system, in which dilute small spheres move in a slowly rearranging, glassy matrix of large spheres. Using confocal differential dynamic microscopy and simulations, we discover a critical size asymmetry at which anomalous collective transport of the small particles appears, manifested as a logarithmic decay of the density autocorrelation functions. We demonstrate that the matrix mobility is central for the observed anomalous behaviour. These results, crucially depending on size-induced dynamic asymmetry, are of relevance for a wide range of phenomena ranging from glassy systems to cell biology.
Behaviour of the model antibody fluid constrained by rigid spherical obstacles: effects of the obstacle-antibody binding
University of Ljubljana, Faculty of Chemistry and Chemical Technology（卢布尔雅那大学化学与化学技术学院）；Yukhnovskii Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine（乌克兰国家科学院尤赫诺夫斯基凝聚态物理研究所）；Institute of Applied Mathematics and Fundamental Sciences, Lviv Polytechnic National University（利沃夫国立理工大学应用数学与基础科学研究所）
Anomalous transport resolved in space and time by fluorescence correlation spectroscopy
在拥挤的细胞膜中普遍观察到的是分子运输不遵循菲克扩散，而是呈现亚扩散。这种行为的微观起源还没有被理解和高度辩论。在这里，我们讨论了两个模型的时空动力学的亚扩散：分数布朗运动和受阻运动由于不动的障碍。我们表明，不同的微观机制，可以区分使用荧光相关光谱（FCS）的共聚焦检测区域的系统变化。我们提供了一个空间分辨FCS的理论框架，通过推广FCS理论超越了空间高斯传输的共同假设。我们推导出FCS自相关函数的主公式，从中可以看出，FCS实验的束腰是一个同样重要的参数，散射实验的波数。这些结果导致两个模型的FCS相关性的标度特性，这是在硅片实验测试。此外，我们的缩放预测与Wawrezinieck等人[Biophys. J. 89，4029（2005）]用于跨膜蛋白的体内实验。
