Mechanics of F-actin microenvironments probed by Brownian particles

By controlling the chemistry of particles embedded in F-actin gels, an attempt was made to demonstrate the important role of actin binding by probes in microrheological measurements. In both uncrosslinked and highly cross-linked networks, particles that bind F-actin report viscoelastic moduli comparable to those determined by macroscopic rheometry. By contrast, particles modified to prevent actin binding have weak microenvironments that are surprisingly insensitive to the introduction of filament cross-links.