title: Microrheology of microtubule solutions and actin-microtubule composite networks.
abstract: We perform local or microrheological measurements on microtubule solutions, as well as composite networks. The viscoelastic properties of microtubules as reported from two-point microrheology agree with the macroscopic measurement at high frequencies, but appear to show a discrepancy at low frequencies, at time scales on the order of a second. A composite of filamentous actin (F-actin) and microtubules has viscoelastic behavior between that of F-actin and pure microtubules. We further show that the Poisson ratio of the composite, measured by the length-scale dependent two-point microrheology, is robustly smaller than that of the F-actin network at time scales tau>1 s, suggesting that a local compressibility is conferred by the addition of microtubules to the F-actin network.
authors.affiliation: Department of Physics, McGill University, Montréal, Canada H3A 2T8.
authors.forename: Vincent
authors.initials: V
authors.lastname: Pelletier
authors.forename: Naama
authors.initials: N
authors.lastname: Gal
authors.forename: Paul
authors.initials: P
authors.lastname: Fournier
authors.forename: Maria L
authors.initials: ML
authors.lastname: Kilfoil
mesh_terms: D000199:Actins / Q000737:chemistry*; D004548:Elasticity; D005453:Fluorescence; D007700:Kinetics; D008870:Microtubules / Q000737:chemistry*; D008956:Models, Chemical; D016012:Poisson Distribution; D012212:Rheology / Q000379:methods; D013997:Time Factors; D055682:Viscoelastic Substances / Q000737:chemistry
chemical_list: D000199:Actins; D055682:Viscoelastic Substances