Liposomes as a model for the study of high frequency dielectrophoresis

Abstract

Liposomes were used as a physical model to study the dielectrophoretic response of single-shelled particles at high frequencies. For a typical particle, the single-shelled theoretical model predicts a lower cross-over frequency that depends upon the dielectric properties of the shell and an upper crossover frequency that depends upon the dielectric properties of the interior. Dried liposomes were rehydrated in media with conductivity ranging from 100 to 2000 μS/cm. The high frequency dielectrophoresis response of the liposomes was observed in the range of 1-80 MHz at 30 volts peak-to-peak, and the upper cross-over frequency was recorded. The experimental results closely matched the theoretical expectations. In particular, the upper cross-over frequency ranged from 9 to 60 MHz and was found to depend linearly on the interior conductivity of the liposome. These results further confirm the single-shell model at high-frequencies. Moreover, they suggest liposomes may be a useful model particle for use during the development of dielectrophoresis-based devices.

Dielectrophoresis: From Molecular to Micrometer-Scale Analytes

“…Peterlin et al 161 studied electro-deformation in phospholipid vesicles using AC electric field and correlated the experimentally observed prolate-tooblate transition frequency ranges with previous literature. 162 Hadady et al 163 used liposomes to study the single-shell DEP model at high frequencies in various conductivity media. They observed an upper crossover frequency in the range of 9−60 MHz and reported a linear dependency of upper crossover frequency on the interior conductivity of liposomes, in agreement with the single-shell DEP theoretical model.…”

Dielectric properties and lamellarity of single liposomes measured by in-liquid scanning dielectric microscopy

“…Lamellarity, determines the stability of liposomes' preparations [10], the amount of lipophilic drugs that can be encapsulated, the kinetics of their release [4] and the fate of liposomes when interacting with cells [7]. Moreover, it also determines the overall mechanical [11] and dielectric [12] properties of the liposomes, which are relevant in their interaction with cells [13,14] or in their electrokinetic manipulation [15]. Finally, when used as cell model systems, strict control of the lamellarity is a pre-requisite [6].…”

Shape deformation of a vesicle under an axisymmetric non-uniform alternating electric field

“…low electric field [33]. This has led to research in designing effective non-uniform electric fields by judicious design of electrodes, often in microfluidic/nanofluidic chips by microfabrication techniques [36,16,35] has gained prominence.Giant Unilamellar Vesicles (Liposomes) (GUVs) have emerged as a very reliable bio-memetic system and has been used to understand the DEP response of cells [37,38]. Unlike biological cells, there are very few experimental [37,39,40] and theoretical [41] investigations on the DEP of vesicles .…”

“…Korlach et al, [42] created a 3D electric field cage to study vesicle deformation and electro-rotation by trapping a vesicle using optical tweezers. Studies on the modification of the electrical properties of GUVs to serve them as test particle for DEP study [43], high-frequency DEP response of vesicles to estimate upper and lower crossover frequency at different interior conductivity and membrane electric properties [38] and DEP studies on surface-modified liposomes in AC fields [39], have also been reported . A vesicle under non-uniform, axisymmetric quadrupole electric field, not only exhibits dielectrophoresis, but can also deform.…”

“…Giant Unilamellar Vesicles (Liposomes) (GUVs) have emerged as a very reliable bio-memetic system and has been used to understand the DEP response of cells [37,38]. Unlike biological cells, there are very few experimental [37,39,40] and theoretical [41] investigations on the DEP of vesicles .…”