Viscoelasticity and its microscopic characterization in semiflexible biopolymer solutions
Plant and animal cells contain a complex polymeric network known as the cytoskeleton. A principal component of this is the actin cortex, a gel-like network of F-actin protein filaments. Recently, solutions of reconstituted F-actin have provided in vitro models of the actin cortex, as well as excellent model systems in which to study semiflexible polymers. We describe models of viscoelasticity in semiflexible polymers, and report theoretical and experimental results for thermal fluctuations of embedded particles, which act as local viscoelastic probes of soft materials such as biopolymer solutions. Specifically, we report high-frequency scaling behavior of the shear modulus, as the 3/4 power of frequency, in contrast with the behavior of flexible polymer systems.
