Nonlinear elastic behaviors and deformation mechanisms of nano-structured crosslinked biopolymer networks

Abstract

Cells always undergo large deformation in response to external stimulations or internal stresses in many cell functions (e.g., cell migration, cell division and cell growth). When undergoing large deformation, crosslinked actin filament networks (CAFNs) always show strong nonlinear elasticity to maintain the cell shape and integrity, known as strain stiffening, which plays a crucial role in many cell functions. To investigate the nonlinear elastic behaviors of CAFNs, a three-dimensional representative volume element model is used to perform finite element method simulations. Simulation results show that actin filament volume fraction, crosslinking density and components’ Young’s moduli show significant influences on the nonlinear elastic behaviors of CAFNs. In addition, the shear stress–strain curves of CAFNs highly depend on the bending stiffness and tensile stiffness of filamins as well as the bending stiffness of actin filaments, however, they are almost insensitive to the tensile stiffness of actin filaments. The present work not only sheds light on the nonlinear elastic behaviors of CAFNs but also provides a valuable reference for developing advanced artificial composite structures that can be used as semi-flexible biomedical scaffolds and wearable electronics.