Phospholipid bilayers are viscoelastic.
Lipid bilayers provide the structural framework for cellular membranes, and their character as two-dimensional fluids enables the mobility of membrane macromolecules. Though the existence of membrane fluidity is well established, the nature of this fluidity remains poorly characterized. Three-dimensional fluids as diverse as chocolates and cytoskeletal networks show a rich variety of Newtonian and non-Newtonian dynamics that have been illuminated by contemporary rheological techniques. Applying particle-tracking microrheology to freestanding phospholipid bilayers, we find that the membranes are not simply viscous but rather exhibit viscoelasticity, with an elastic modulus that dominates the response above a characteristic frequency that diverges at the fluid-gel (L(α) - L(β)) phase-transition temperature. These findings fundamentally alter our picture of the nature of lipid bilayers and the mechanics of membrane environments.
Harland
Christopher W
CW
Department of Physics, Materials Science Institute, and Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA.
Bradley
Miranda J
MJ
Parthasarathy
Raghuveer
R
D004548:Elasticity; D008051:Lipid Bilayers / Q000737:chemistry*; D008560:Membrane Fluidity; D044367:Phase Transition; D010743:Phospholipids / Q000737:chemistry; D012212:Rheology; D014783:Viscosity
D008051:Lipid Bilayers; D010743:Phospholipids