Rapid local compression in active gels is caused by nonlinear network response

D. Mizuno, C. Tardin, C. F. Schmidt

Research output: Contribution to journalArticlepeer-review

Abstract

The actin cytoskeleton in living cells generates forces in conjunction with myosin motor proteins to directly and indirectly drive essential cellular processes. The semiflexible filaments of the cytoskeleton can respond nonlinearly to the collective action of motors. We here investigate mechanics and force generation in a model actin cytoskeleton, reconstituted in vitro, by observing the response and fluctuations of embedded micron-scale probe particles. Myosin mini-filaments can be modeled as force dipoles and give rise to deformations in the surrounding network of cross-linked actin. Anomalously correlated probe fluctuations indicate the presence of rapid local compression or draining of the network that emerges in addition to the ordinary linear shear elastic (incompressible) response to force dipoles. The anomalous propagation of compression can be attributed to the nonlinear response of actin filaments to the microscopic forces, and is quantitatively consistent with motor-generated large-scale stiffening of the gels.

Original languageEnglish
Pages (from-to)9369-9382
Number of pages14
JournalSoft Matter
Volume16
Issue number40
DOIs
Publication statusPublished - Oct 28 2020

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Condensed Matter Physics

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