Microrheology of filament networks from Brownian dynamics simulations

Abstract

Microrheology is a technique that have been largely used to investigate viscoelasticity in biological systems. For example, it revealed that filament networks, which are the main component of the citoskeleton of eukaryote cells, show an interesting semisolid viscoelastic response that is characterized by a hardening behaviour at high frequencies. Here, we adopt a computational approach based on microrheology to study the relationship between the Brownian motion of probe particles immersed in a filament network and its viscoelastic response. In particular, we consider a simple model for the filament networks and perform Brownian dynamics simulations to obtain the mean-squared displacement of probe particles, which is used to evaluate the shear moduli G' and G" of the networks. Our numerical results indicate that the proposed numerical approach can reproduce several features observed in experiments, including the sol-gel transition observed when varying the density of filaments, and the aforementioned hardening behaviour at high frequencies.