FIG. 3.

Mechanical properties of an ATN. (A) Cartoon of an isogonal ‘breathing mode’ of a cell in a tension net. (B) Because ATN equilibrium is a manifold rather than a point, after a transient perturbation the system does not necessarily return to the same state, resulting in an ‘isogonal’ transformation. (C) Amplitude and (D) phase of the longitudinal strain (as a function of position) in response to periodic uniaxial forcing T_B cosωt applied at the boundaries (κ = 10⁻² and ᾱ = 10⁻⁴). As the frequency ω decreases below ᾱ the phase shifts from π/2 to 0 indicating crossover from viscous fluid behavior to an elastic solid. This contrasts with the conventional Maxwellian viscoelasticity crossover towards elasticity with ω increasing above κ (see SI for details).