A new approach to model cross-linked actin networks: Multi-scale continuum formulation and computational analysis
2013 (English)In: Journal of The Mechanical Behavior of Biomedical Materials, ISSN 1751-6161, Vol. 22, 95-114 p.Article in journal (Refereed) Published
The mechanical properties of a cell are defined mainly by the cytoskeleton. One contributor within this three-dimensional structure is the actin cortex which is located underneath the lipid bilayer. It forms a nearly isotropic and densely cross-linked protein network. We present a continuum mechanical formulation for describing the mechanical properties of in vitro model systems based on their micro-structure, i.e. the behavior of a single filament and its spatial arrangement. The network is considered elastic, viscous effects being neglected. Filamentous actin is a biopolymer with a highly nonlinear force-stretch relationship. This can be well described by a worm-like chain model that includes extensibility of the filament, which we call the . β-model. A comparison with experimental data shows good agreement with values for the physically interpretable parameters. To make these properties applicable to three dimensions we used a non-affine micro-sphere network, which accounts for filaments, equally distributed in space. The assembled model results in a strain-energy density which is a function of the deformation gradient, and it is validated with experimental data from rheological experiments of in vitro reconstituted actin networks. The Cauchy stress and elasticity tensors are obtained within the continuum mechanics framework and implemented into a finite element program to solve boundary-value problems.
Place, publisher, year, edition, pages
2013. Vol. 22, 95-114 p.
Actin network, Continuum mechanics, Micro-sphere, Worm-like chain
IdentifiersURN: urn:nbn:se:kth:diva-134278DOI: 10.1016/j.jmbbm.2012.11.019ISI: 000320088500010ScopusID: 2-s2.0-84877794746OAI: oai:DiVA.org:kth-134278DiVA: diva2:666916
QC 201311252013-11-252013-11-202013-11-25Bibliographically approved