title: Intracellular micro-rheology probed by micron-sized wires.
abstract: In the last decade, rapid advances have been made in the field of micro-rheology of cells and tissues. Given the complexity of living systems, there is a need for the development of new types of nano- and micron-sized probes, and in particular of probes with controlled interactions with the surrounding medium. In the present paper, we evaluate the use of micron-sized wires as potential probes of the mechanical properties of cells. The wire-based micro-rheology technique is applied to living cells such as murine fibroblasts and canine kidney epithelial cells. The mean-squared angular displacement of wires associated to their rotational dynamics is obtained as a function of the time using optical microscopy and image processing. It reveals a Brownian-like diffusive regime of the form Δψ(2)(t,L) ≈ t/L(3), where L denotes the wire length. This scaling suggests that an effective viscosity of the intracellular medium can be determined, and that in the range 1-10 μm it does not depend on the length scale over which it is measured.
authors.affiliation: Laboratoire Matière et Systèmes Complexes (MSC), UMR 7057 CNRS & Université Paris Diderot, Bâtiment Condorcet, 10 rue Alice Domon et Léonie Duquet, 75205 Paris, France.
authors.forename: Loudjy
authors.initials: L
authors.lastname: Chevry
authors.forename: Rémy
authors.initials: R
authors.lastname: Colin
authors.forename: Bérengère
authors.initials: B
authors.lastname: Abou
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Berret
mesh_terms: D000818:Animals; D002460:Cell Line; D003593:Cytoplasm / Q000737:chemistry / Q000648:ultrastructure*; D004285:Dogs; D004847:Epithelial Cells / Q000737:chemistry / Q000648:ultrastructure; D005347:Fibroblasts / Q000737:chemistry / Q000648:ultrastructure; D059346:Magnets / Q000032:analysis; D051379:Mice; D008853:Microscopy; D041681:NIH 3T3 Cells; D012212:Rheology / Q000295:instrumentation*; D014783:Viscosity