A microstructurally informed model for the mechanical response of three-dimensional actin networks

Abstract

We propose a class of microstructurally informed models for the linear elastic mechanical behaviour of cross-linked polymer networks such as the actin cytoskeleton. Salient features of the models include the possibility to represent anisotropic mechanical behaviour resulting from anisotropic filament distributions, and a power law scaling of the mechanical properties with the filament density. Mechanical models within the class are parameterized by seven different constants. We demonstrate a procedure for determining these constants using finite element models of three-dimensional actin networks. Actin filaments and cross-links were modelled as elastic rods, and the networks were constructed at physiological volume fractions and at the scale of an image voxel. We show the performance of the model in estimating the mechanical behaviour of the networks over a wide range of filament densities and degrees of anisotropy.

Keywords:

• homogenization
• constitutive model
• finite element model
• actin cytoskeleton
• cell mechanics

Keywords:

• 74D05
• 74K10
• 74S05
• 74E10

Acknowledgements

We would like to acknowledge grant AR45989 from the National Institutes of Health, the National Science Foundation Graduate Fellowship, and the Veterans Affairs Palo Alto Bone and Joint Center for funding.

Notes

^1. SE, standard error; n, number of samples.