Transient electrodeformation of giant unilamellar vesicles

The electrodeformation of giant vesicles provides fundamental insights into the electro-mechanical coupling of transmembrane potential and membrane shapes. The steady shape of a giant vesicle (~ 10-50 micron in radius) in a uniform AC field is widely used to measure membrane elastic properties such as bending rigidity and tension. We utilize the time dependent vesicle shape to extract dynamic properties such as membrane viscosity and capacitance. The method is applied to characterize membranes made of lipids and block-copolymers (polymersomes). We study the vesicle shape in a uniform AC electric field after change in field strength at a fixed frequency or after frequency change at a fixed field. Theoretical analysis and experimental quantification are provided for the deformation and relaxation of vesicles. Agreement allows for a robust measurement of membrane viscosity for different types and phases.