Microrheology

Several complementary techniques have been developed in recent years that make it possible to measure viscoelastic properties of soft materials on micrometer scales. Such methods provide new prospects for the characterization of local inhomogeneities in materials, for studies of material properties in small samples, including living cells, and for high frequency rheology. The main techniques discussed in this review are magnetic bead manipulation, observation of refractive beads with laser interferometry or multiply scattered light, and atomic force microscopy. Materials studied include synthetic polymers, thin polymer films, biological polymers in vitro and in vivo. (C) 1999 Elsevier Science Ltd. All rights reserved.