Non-Gaussian athermal fluctuations in active gels
By Toshihiro Toyota, D. Head, C. Schmidt, D. Mizuno. 2011
139 citations recorded by the source corpus.
Dynamic networks designed to model the cell cytoskeleton can be reconstituted from filamentous actin, the motor protein myosin and a permanent cross-linker. They are driven out of equilibrium when the molecular motors are active. This gives rise to athermal fluctuations that can be recorded by tracking probe particles that are dispersed in the network. We have here probed athermal fluctuations in such “active gels” using video microrheology. We have measured the full distribution of probe displacements, also known as the van Hove correlation function. The dominant influence of thermal or athermal fluctuations can be detected by varying the lag time over which the displacements are measured. We argue that the exponential tails of the distribution derive from single motors close to the probes, and we extract an estimate of the velocity of motor heads along the actin filaments. The distribution exhibits a central Gaussian region which we assume derives from the action of many independent motor proteins far from the probe particles when athermal fluctuations dominate. Recording the whole distribution rather than just the typically measured second moment of probe fluctuations (mean-squared displacement) thus allowed us to differentiate between the effect of individual motors and the collective action of many motors.
Subfields: Condensed Matter Physics, Materials Chemistry, Statistical and Nonlinear Physics
View Paper: https://www.semanticscholar.org/paper/be07c341dfe62c2b36409df8a4ff898f8e656f1f
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In Materials Chemistry
Citations in the corpus
- Particle tracking in living cells: a review of the mean square displacement method and beyond (2013, background): “Similar α2(τ ) plots have been attributed to small non-thermal driving forces (Toyota et al. 2011), which are likely in the dense intracellular microenvironment.”