Microrheology probes length scale dependent rheology

We exploit the power of microrheology to measure the
viscoelasticity of entangled F-actin solutions at different length
scales from 1 to 100 mu m over a wide frequency range. We compare
the behavior of single probe-particle motion to that of the
correlated motion of two particles. By varying the average length
of the filaments, we identify fluctuations that dissipate
diffusively over the filament length. These provide an important
relaxation mechanism of the elasticity between 0.1 and 30 rad/sec.