title: Mechanical plasticity of cells.
abstract: Under mechanical loading, most living cells show a viscoelastic deformation that follows a power law in time. After removal of the mechanical load, the cell shape recovers only incompletely to its original undeformed configuration. Here, we show that incomplete shape recovery is due to an additive plastic deformation that displays the same power-law dynamics as the fully reversible viscoelastic deformation response. Moreover, the plastic deformation is a constant fraction of the total cell deformation and originates from bond ruptures within the cytoskeleton. A simple extension of the prevailing viscoelastic power-law response theory with a plastic element correctly predicts the cell behaviour under cyclic loading. Our findings show that plastic energy dissipation during cell deformation is tightly linked to elastic cytoskeletal stresses, which suggests the existence of an adaptive mechanism that protects the cell against mechanical damage.
authors.affiliation: Department of Physics, University of Erlangen-Nuremberg, 91054 Erlangen, Germany.|Max-Planck Institute for the Science of Light, 91058 Erlangen, Germany.
authors.forename: Navid
authors.initials: N
authors.lastname: Bonakdar
authors.affiliation: Department of Physics, University of Erlangen-Nuremberg, 91054 Erlangen, Germany.
authors.forename: Richard
authors.identifier: 0000-0001-5893-2650
authors.initials: R
authors.lastname: Gerum
authors.affiliation: Department of Physics, University of Erlangen-Nuremberg, 91054 Erlangen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Kuhn
authors.affiliation: Department of Physics, University of Erlangen-Nuremberg, 91054 Erlangen, Germany.
authors.forename: Marina
authors.initials: M
authors.lastname: Spörrer
authors.affiliation: Department of Physics, University of Erlangen-Nuremberg, 91054 Erlangen, Germany.
authors.forename: Anna
authors.initials: A
authors.lastname: Lippert
authors.affiliation: Department of Physics, University of Erlangen-Nuremberg, 91054 Erlangen, Germany.
authors.forename: Werner
authors.initials: W
authors.lastname: Schneider
authors.affiliation: Department of Civil Engineering and Engineering Mechanics, University of Arizona, Tucson, Arizona 85721, USA.
authors.forename: Katerina E
authors.initials: KE
authors.lastname: Aifantis
authors.affiliation: Department of Physics, University of Erlangen-Nuremberg, 91054 Erlangen, Germany.
authors.forename: Ben
authors.initials: B
authors.lastname: Fabry