Curvature fluctuations of fluid vesicles reveal hydrodynamic dissipation within the bilayer

Hammad A. Faizi, Rony Granek, Petia M. Vlahovska

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

The biological function of membranes is closely related to their softness, which is often studied through the membranes’ thermally driven fluctuations. Typically, the analysis assumes that the relaxation rate of a pure bending deformation is determined by the competition between membrane bending rigidity and viscous dissipation in the surrounding medium. Here, we reexamine this assumption and demonstrate that viscous flows within the membrane dominate the dynamics of bending fluctuations of nonplanar membranes with a radius of curvature smaller than the Saffman–Delbrück length. Using flickering spectroscopy of giant vesicles made of dipalmitoylphosphatidylcholine, DPPC:cholesterol mixtures and pure diblock-copolymer membranes, we experimentally detect the signature of membrane dissipation in curvature fluctuations. We show that membrane viscosity can be reliably obtained from the short time behavior of the shape time correlations. The results indicate that the DPPC:cholesterol membranes behave as a Newtonian fluid, while the polymer membranes exhibit more complex rheology. Our study provides physical insights into the time scales of curvature remodeling of biological and synthetic membranes.

Original languageEnglish
Article numbere2413557121
JournalProceedings of the National Academy of Sciences of the United States of America
Volume121
Issue number44
DOIs
StatePublished - 29 Oct 2024

Keywords

  • curvature fluctuations
  • lipid bilayer
  • membrane viscosity
  • polymersome
  • vesicle

ASJC Scopus subject areas

  • General

Fingerprint

Dive into the research topics of 'Curvature fluctuations of fluid vesicles reveal hydrodynamic dissipation within the bilayer'. Together they form a unique fingerprint.

Cite this