Figure 4. Master curve for wire average rotation velocity in cells.

(a) Average rotation velocity Ω(ω) of a magnetic wire calculated for a Newtonian fluid, for a viscoelastic liquid (indicated as VEL) and for an elastic gel according to a set of models listed in Supplementary Note 1. For the sake of convenience, the viscous and the viscoelastic liquids have here the same static viscosity and ω_C=1 rad s⁻¹. (b) Ω(ω)-evolution for wires of lengths between 1.9 and 5.9 μm internalized in the cytoplasm of mouse fibroblasts. The continuous lines (from equation (1)) indicate the existence of a critical frequency in the rotation dynamics. (c) Data from Fig. 4b plotted in reduced units, Ω/ω_C versus ω/ω_C. The continuous lines are Ω(X)=X and for X≤1 and X≥1, respectively. Error bars in b,c are defined as s.e.m.