New insights into diffusion in 3D crowded media by Monte Carlo simulations: Effect of size, mobility and spatial distribution of obstacles

Particle diffusion in crowded media was studied through Monte Carlo simulations in 3D obstructed lattices. Three particular aspects affecting the diffusion, not extensively treated in three-dimensional geometry, were analysed: the relative particle-obstacle size, the relative particle-obstacle mobil...

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Detalles Bibliográficos
Autores: Vilaseca i Font, Eudald, Isvoran, Adriana, Madurga Díez, Sergio, Pastor, Isabel, Garcés, Josep Lluís, Mas i Pujadas, Francesc
Tipo de recurso: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2011
País:España
Institución:Universidad de Barcelona
Repositorio:Dipòsit Digital de la UB
OAI Identifier:oai:diposit.ub.edu:2445/109040
Acceso en línea:https://hdl.handle.net/2445/109040
Access Level:acceso abierto
Palabra clave:Mètode de Montecarlo
Difusió
Teoria de models
Macromolècules
Monte Carlo method
Diffusion
Model theory
Macromolecules
Descripción
Sumario:Particle diffusion in crowded media was studied through Monte Carlo simulations in 3D obstructed lattices. Three particular aspects affecting the diffusion, not extensively treated in three-dimensional geometry, were analysed: the relative particle-obstacle size, the relative particle-obstacle mobility and the way of having the obstacles distributed in the simulation space (randomly or uniformly). The results are interpreted in terms of the parameters that characterize the time dependence of the diffusion coefficient: the anomalous diffusion exponent (), the crossover time from anomalous to normal diffusion regimes (τ) and the long time diffusion coefficient (D*). Simulation results indicate that there is a more anomalous diffusion (smaller ) and lower long time diffusion coefficient (D*) when obstacle concentration increases, and that, for a given total excluded volume and immobile obstacles, the anomalous diffusion effect is less important for bigger size obstacles. However, for the case of mobile obstacles, this size effect is inverted yielding values that are in qualitatively good agreement with in vitro experiments of protein diffusion in crowded media. These results underline that the pattern of the spatial partitioning of the obstacle-excluded volume is a factor to be considered together with the value of the excluded volume itself.