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Viscoelasticity of cross-linked actin networks: Experimental tests, mechanical modeling and finite-element analysis

Paper ID Volume ID Publish Year Pages File Format Full-Text
530 46 2013 11 PDF Available
Title
Viscoelasticity of cross-linked actin networks: Experimental tests, mechanical modeling and finite-element analysis
Abstract

Filamentous actin is one of the main constituents of the eukaryotic cytoskeleton. The actin cortex, a densely cross-linked network, resides underneath the lipid bilayer. In the present work we propose a continuum mechanical formulation for describing the viscoelastic properties of in vitro actin networks, which serve as model systems for the cortex, by including the microstructure, i.e. the behavior of a single filament and its spatial arrangement. The modeling of the viscoelastic response in terms of physically interpretable parameters is conducted using a multiscale approach consisting of two steps: modeling of the single filament response of F-actin by a worm-like chain model including the extensibility of the filament, and assembling the three-dimensional biopolymer network by using the microsphere model which accounts for filaments equally distributed in space. The viscoelastic effects of the network are taken into account using a generalized Maxwell model. The Cauchy stress and elasticity tensors are obtained within a continuum mechanics framework and implemented into a finite-element program. The model is validated on the network level using large strain experiments on reconstituted actin gels. Comparisons of the proposed model with rheological experiments recover reasonable values for the material parameters. Finite-element simulations of the indentation of a sphere on a network slab and the aspiration of a droplet in a micropipette allow for further insights of the viscoelastic behavior of actin networks.

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Keywords
Actin network; Continuum mechanics; Worm-like chain; Microsphere; Viscoelasticity
First Page Preview
Viscoelasticity of cross-linked actin networks: Experimental tests, mechanical modeling and finite-element analysis
Publisher
Database: Elsevier - ScienceDirect
Journal: Acta Biomaterialia - Volume 9, Issue 7, July 2013, Pages 7343–7353
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering