In contrast with entangled actin solutions, transiently cross-linked actin networks can provide highly elastic properties while still allowing for local rearrangements in the microstructure-on biological relevant time scales. Here, we show that thermal unbinding of transient cross-links entails local stress relaxation and energy dissipation in an intermediate elasticity dominated frequency regime. We quantify the viscoelastic response of an isotropically cross-linked actin network by experimentally tuning the off rate of the transiently cross-linking molecules, their density, and the solvent viscosity. We reproduce the measured frequency response by a semiphenomenological model that is predicated on microscopic unbinding events.
Lieleg, O., Claessens, M. M. A. E., Luan, Y., & Bausch, A. R. (2008). Transient Binding and Dissipation in Cross-Linked Actin Networks. Physical review letters, 101(10), 108101-1-108101-4. https://doi.org/10.1103/PhysRevLett.101.108101