Active rheology of phospholipid vesicles

Aidan T. Brown, Jurij Kotar, Pietro Cicuta*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Optical tweezers are used to manipulate the shape of artificial dioleoyl-phosphatidylcholine (DOPC) phospholipid vesicles of around 30 mu m diameter. Using a time-shared trapping system, a complex of traps drives oscillations of the vesicle equator, with a sinusoidal time dependence and over a range of spatial and temporal frequencies. The mechanical response of the vesicle membrane as a function of the frequency and wavelength of the driving oscillation is monitored. A simple model of the vesicles as spherical elastic membranes immersed in a Newtonian fluid, driven by a harmonic trapping potential, describes the experimental data. The bending modulus of the membrane is recovered. The method has potential for future investigation of nonthermally driven systems, where comparison of active and passive rheology can help to distinguish nonthermal forces from equilibrium fluctuations.

Original languageEnglish
Article number021930
Number of pages9
JournalPhysical Review E - Statistical, Nonlinear and Soft Matter Physics
Volume84
Issue number2
DOIs
Publication statusPublished - 25 Aug 2011

Keywords

  • THERMAL FLUCTUATIONS
  • FLUID MEMBRANES
  • UNDULATIONS
  • CURVATURE
  • CELLS
  • DEPENDENCE
  • ELASTICITY
  • RIGIDITY
  • SHAPE

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