Compound giant unilamellar vesicles as a bio-mimetic model for electrohydrodynamics of a nucleate cell.

The understanding obtained by studies on the electrohydrodynamics (EHD) of single giant unilamellar vesicles (sGUVs) has contributed significantly towards a better comprehension of the response of biological cells to electric fields. This has subsequently helped in developing technologies such as cell dielectrophoresis and cell electroporation. For nucleate eukaryotic cells though, a vesicle-in-vesicle compound giant unilamellar vesicle (cGUV) is a more appropriate bio-mimic than a sGUV. In this work, we present an improvised method for the formation of cGUVs, wherein the electrical conductivities of the inner, annular and outer regions of the cGUVs can be modified. A comprehensive experimental study is presented on the EHD of these cGUVs under weak AC fields over a wide range of frequencies, and an encouraging agreement is observed between the experiments and earlier published theoretical studies on concentric cGUVs. The spherical, prolate or oblate spheroidal deformations of a cGUV under AC electric fields depend upon the membrane electromechanical properties as well as the magnitude and direction of the electric traction at the membrane produced by the Maxwell stress that varies with the relative timescales associated with the frequency of the applied AC electric field and that of the membrane charging time and the Maxwell-Wagner relaxation time. This work establishes cGUVs as appropriate bio-mimics for conducting EHD studies relevant to eukaryotic cells.