Cross-linked actin network: Micro- and macroscopic effects

Actin plays a crucial role in the mechanical response of cells. Together with other proteins, it also drives protrusion,motilityand cell division. Two important aspects of the mechanical modeling of this kind of protein are considered: its microscopicand macroscopic behavior. At the microscopic level, we start with a model proposed by Holzapfel and Ogden [1] providinga relationship between the stretch of a single polymer chainand the applied tension force. The model is advantageous as itsimulates the so-called ‘exceptional normal stresses’. This effect is typical for biopolymers and contradicts with the Poyntingeffect typically observed in rubber-like polymers. The multiscale finite element method (FEM) is applied to simulate theeffective mechanical behavior of cell cytoplasm.