ABSTRACT
Membranes constitute a ubiquitous component of tissues as they hold cells
together and divide them into compartments. They are formed mainly of an
assembly of a wide variety of lipids, proteins, and carbohydrates that self-
organize into a thin barrier that separates the interior of the cell from the
outside environment [1]. The main lipid constituents of cell membranes are
phospholipids-amphiphilic molecules that have a hydrophilic head and two
hydrophobic tails. When lipids are exposed to water, they arrange themselves
into a two-layered sheet (a bilayer) with all of their tails pointing toward the
center of the sheet. Although the bilayers are only a few nanometers thick,
these are impermeable to most water-soluble (hydrophilic) molecules.
