Microrheology of microtubule solutions and actin-microtubule composite networks

Phys Rev Lett. 2009 May 8;102(18):188303. doi: 10.1103/PhysRevLett.102.188303. Epub 2009 May 7.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / chemistry*
  • Elasticity
  • Fluorescence
  • Kinetics
  • Microtubules / chemistry*
  • Models, Chemical
  • Poisson Distribution
  • Rheology / methods
  • Time Factors
  • Viscoelastic Substances / chemistry


  • Actins
  • Viscoelastic Substances