Computational Study Of Diffusion In Cellulartwo-dimensional Crowded Media Modeled As Mixturesrnof Mobile And Immobile Obstacles

摘要

The aim of this paper is to reveal how diffusion in cellular obstructed media is affected by obstacles' mobility using a Monte Carlo simulation algorithm. Macromolecular crowding is a characteristic of cellular media and it has strong effects on many physical and chemical phenomena, diffusion being one of the most affected. We model small particles diffusion processes in cell membranes using two-dimensional lattices with obstacles having different sizes and different degrees of mobility. There are two types of obstacles: the first ones mimic membrane proteins, are bigger and immobile and the second ones mimic membrane lipids, are smaller and have different degrees of mobility. Our simulations show that in all obstructed lattices diffusion is anomalous for short times and becomes normal for long times. They also reveal that for increasing mobility of obstacles diffusion is less anomalous and the crossover time from one regime to another decreases with increasing mobility of obstacles. These results reflect that membrane fluidity strongly facilitates small particles diffusion processes and underline the applicability of these kind of computational studies for analysing molecular diffusion in cellular media.