Actin/NMMIIB–ADP networks shear thicken. (a) Effective viscosity, ηeff, as a function of applied stress, σ0 for entangled F-actin solution, R = 0 (closed squares), and actin/NMMIIB–ADP networks with R = 0.025 (open circles) and R = 0.05 (closed triangles). (b) Stress relaxation time scale, τ, as a function of applied stress, σ0 for actin/NMMIIB–ADP networks with R = 0.05. (c) The unrecovered strain after a creep measurement, defined as the difference in the strain prior to a creep measurement and after the recovery phase, as a function of applied stress. Entangled actin solutions (solid squares) and actin/NMMIIB–ADP networks formed with R = 0.025 (open circles) and R = 0.05 (closed triangles).