Eur. Phys. J. Special Topics 204, 75-84 (2012)
https://doi.org/10.1140/epjst/e2012-01553-y

Regular Article

Diffusion inside living human cells

¹ Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen Ø, Denmark
² Department of Physics, Tampere University of Technology, 33101 Tampere, Finland
³ Institute for Physics and Astronomy, University of Potsdam, 14476 Potsdam-Golm, Germany
⁴ Institute for Public Health, University of Copenhagen, Øster Farimagsgade 5, 1014 Copenhagen K, Denmark

^a e-mail: oddershede@nbi.dk

Received: 23 December 2011
Revised: 22 February 2012
Published online: 17 April 2012

Abstract

Naturally occurring lipid granules diffuse in the cytoplasm and can be used as tracers to map out the viscoelastic landscape inside living cells. Using optical trapping and single particle tracking we found that lipid granules exhibit anomalous diffusion inside human umbilical vein endothelial cells. For these cells the exact diffusional pattern of a particular granule depends on the physiological state of the cell and on the localization of the granule within the cytoplasm. Granules located close to the actin rich periphery of the cell move less than those located towards to the center of the cell or within the nucleus. Also, granules in cells which are stressed by intense laser illumination or which have attached to a surface for a long period of time move in a more restricted fashion than those within healthy cells. For granules diffusing in healthy cells, in regions away from the cell periphery, occurrences of weak ergodicity breaking are observed, similar to the recent observations inside living fission yeast cells [1].