Liposomes form nanotubules and long range networks in the presence of electric field

Liposomes are lipid bilayer-bound micron scale structures critical to therapeutic treatments, biophysical studies, cosmetics, food, constrained volume experiments, and gene transfer. ^1-8 Applying an electric field to separate mixtures of liposomes played a role in their discovery and is still presently used for a variety of processes. ^{1,9 10} Our group has found agreement between models of electric field-induced transport and capillary electrophoresis measurements where the liposomes are described as slightly elongated with the charged lipids migrating to form a local dipole. ¹¹ Here we show much more diverse structures that cannot be accounted for in these models. A variety of morphologies emerge, from individual liposomes being stretched into nanotubules several microns in length to long-range organized assemblies of liposomes over tens of microns. Based in this result, existing theories for electromigration of soft particles need to be re-addressed. Also, the formation of nanoscale lipid tubules suggests that unique structures for bionanoengineering can be fabricated. Much higher intrinsic fields than those applied here are observed in biology that suggests mechanical electrostatic interaction may play role in shape and function of individual biological membranes and networks of membrane-bound structures.