Fractal dimension of the trajectory of a single particle diffusing in crowded media

Abstract

Using Monte Carlo simulations we have modeled the diffusion of a single particle in twoand three-dimensional lattices with different crowding conditions given by distinct obstacles size and density. All registered data emphasize that diffusion process is anomalous and diffusing particle describes fractal trajectories. We have introduced a new time-scale fractal dimension, dm, which is related to the anomalous diffusion exponent, α. This allows us to relate the well-known length-scale fractal dimension of the random walk, dw, to the new one introduced here as a time-scale fractal dimension. Moreover, the 3D simulations consider similar conditions to those used in our previous FRAP experiments in order to reveal the relationship between the length and time-scale fractal dimensions.