Probing active forces via a fluctuation-dissipation relation: Application to living cells
1 Laboratoire Matière et Systèmes Complexes, CNRS UMR 7057, Université Paris Diderot 10 rue Alice Domon et Léonie Duquet, F-75205 Paris cedex 13, France, EU
2 Instituut voor Theoretische Fysica, KU Leuven - Celestijnenlaan 200D, B-3001 Leuven, Belgium, EU
Received: 22 January 2013
Accepted: 27 May 2013
We derive a new fluctuation-dissipation relation for non-equilibrium systems with long-term memory. We show how this relation allows one to access new experimental information regarding active forces in living cells that cannot otherwise be accessed. For a silica bead attached to the wall of a living cell, we identify a crossover time between thermally controlled fluctuations and those produced by the active forces. We show that the probe position is eventually slaved to the underlying random drive produced by the so-called active forces.
PACS: 05.40.-a – Fluctuation phenomena, random processes, noise, and Brownian motion / 87.18.Tt – Noise in biological systems / 87.16.Nn – Motor proteins (myosin, kinesin dynein)
© EPLA, 2013