High-Resolution Probing of Cellular Force Transmission

Mizuno, Daisuke; Bacabac, Rommel G.; Tardin, Catherine; Head, D. A.; Schmidt, Christoph F.

doi:10.1103/physrevlett.102.168102

Cited by 85 publications

(93 citation statements)

References 31 publications

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“…While such a stiffening can also arise from an increase of mechanical crosslinking, e.g., due to dead or inactive myosins, Mizuno et al, were able to confirm that there was a significant increase in network tension that was coincident with the mechanical stiffening, consistent with a mechanisms due to network nonlinearity. These authors were also able to demonstrate directly the non-equilibirum nature of both reconstituted and living systems (Mizuno et al, 2009(Mizuno et al, , 2008(Mizuno et al, , 2007. Interestingly, analogous behavior is beginning to be studied in synthetic systems (Bertrand et al, 2012).…”

Section: Comparison Of the Affine Model To Experiments On Reconstitutmentioning

confidence: 90%

Modeling semiflexible polymer networks

2014

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Here, we provide an overview of theoretical approaches to semiflexible polymers and their networks. Such semiflexible polymers have large bending rigidities that can compete with the entropic tendency of a chain to crumple up into a random coil. Many studies on semiflexible polymers and their assemblies have been motivated by their importance in biology. Indeed, crosslinked networks of semiflexible polymers form a major structural component of tissue and living cells. Reconstituted networks of such biopolymers have emerged as a new class of biological soft matter systems with remarkable material properties, which have spurred many of the theoretical developments discussed here. Starting from the mechanics and dynamics of individual semiflexible polymers, we review the physics of semiflexible bundles, entangled solutions and disordered cross-linked networks. Finally, we discuss recent developments on marginally stable fibrous networks, which exhibit critical behavior similar to other marginal systems such as jammed soft matter.

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Section: Comparison Of the Affine Model To Experiments On Reconstitutmentioning

confidence: 90%

Modeling semiflexible polymer networks

2014

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“…Probing the response of adherent cells from the outside (17,47) typically results in elastic moduli in the kPa range, reflecting the elastic behavior of the dense actin network of the cortex (48,49). Some experiments have addressed the elastic response of suspended rounded cells to external forces (50,51), showing relatively low stiffness, likely to still be dominated by the actin cortex. Some studies have directly addressed the mesoscale viscoelasticity of intracellular networks and the cytosol (23,29,42,44,(52)(53)(54).…”

Section: Discussionmentioning

confidence: 99%

The Mechanical Properties of Early Drosophila Embryos Measured by High-Speed Video Microrheology

Wessel

Gumalla

Großhans

et al. 2015

Biophysical Journal

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In early development, Drosophila melanogaster embryos form a syncytium, i.e., multiplying nuclei are not yet separated by cell membranes, but are interconnected by cytoskeletal polymer networks consisting of actin and microtubules. Between division cycles 9 and 13, nuclei and cytoskeleton form a two-dimensional cortical layer. To probe the mechanical properties and dynamics of this self-organizing pre-tissue, we measured shear moduli in the embryo by high-speed video microrheology. We recorded position fluctuations of injected micron-sized fluorescent beads with kHz sampling frequencies and characterized the viscoelasticity of the embryo in different locations. Thermal fluctuations dominated over nonequilibrium activity for frequencies between 0.3 and 1000 Hz. Between the nuclear layer and the yolk, the cytoplasm was homogeneous and viscously dominated, with a viscosity three orders of magnitude higher than that of water. Within the nuclear layer we found an increase of the elastic and viscous moduli consistent with an increased microtubule density. Drug-interference experiments showed that microtubules contribute to the measured viscoelasticity inside the embryo whereas actin only plays a minor role in the regions outside of the actin caps that are closely associated with the nuclei. Measurements at different stages of the nuclear division cycle showed little variation.

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“…By measuring the response function and spontaneous fluctuations for the same system and for the same experimental conditions, it is possible to assert directly the presence of " 2 non-equilibrium processes, as recently demonstrated in vitro for hair bundles 29 , active gels 30 and suspended bone cells 31 . A series of techniques allow the measurement of cellular mechanics 32 , and the RBC membrane response was measured previously using micropipette aspiration 33 , electric fields 34 , or optical tweezers 10,35 , but never compared directly to the fluctuations in the same cell.…”

Section: Main Textmentioning

confidence: 99%