Paper Number
IR28 

Session
Interfacial Rheology

Title
Shear viscosity effect on lipid membrane undulations and dynamic structure factor of liposomes

Presentation Date and Time
October 11, 2022 (Tuesday) 2:50

Track / Room
Track 5 / Sheraton 2

Authors (Click on name to view author profile)

  1. Vlahovska, Petia M. (Northwestern University)
  2. Faizi, Hammad A. (Northwestern University)
  3. Granek, Rony (Ben-Gurion University of The Negev)

Author and Affiliation Lines (in printed abstract book)
Petia M. Vlahovska1, Hammad A. Faizi1 and Rony Granek2
1Northwestern University, Evanston, IL; 2Ben-Gurion University of The Negev, Beer-Sheva, Israel

Speaker / Presenter 
Vlahovska, Petia M.

Keywords
theoretical methods; bio-fluids; biomaterials; interfacial rheology; surfactants

Text of Abstract
Membrane viscosity is usually neglected when analyzing the thermally-driven undulations and the dynamic structure factor of lipid bilayers. While this assumption is valid for planar membranes, here we show that fluctuations about a curved shape such as a quasi-spherical vesicle are sensitive to the membrane viscosity on length-scales comparable to the radius of curvature. For modes with wavelength shorter than the Saffman-Delbruck length, the relaxation rates of the shape time-correlations of a tension-free vesicle show a modified power-law dependence on the wavenumber q between q^3 and q^4, instead of the classic result q^3. The theoretical predictions are verified against experimental data from flickering of giant vesicles made of DPPC:Chol. The dynamic structure factor is also modified, suggesting that the analysis of data obtained from dynamic methods such as Neutron Spin Echo of liposomes should be reassessed.