Efforts to describe and model the molecular structure of biological
membranes go back to the beginning of the last century. In 1917,
Langmuir described membranes as a layer of lipids one molecule thick
[1]. Eight years later, Gorter and Grendel concluded from their
studies that "the phospholipid molecules that formed the cell membrane
were arranged in two layers to form a lipid bilayer" [2]. Danielli and
Robertson proposed, in 1935, a model in which the bilayer of lipids is
sequestered between two monolayers of unfolded proteins [3], and the
currently still accepted fuid mosaic model was proposed by Singer and
Nicolson in 1972 [4]. Among those landmarks of biomembrane history, a
serendipitous observation made by Alex Bangham during the early 1960s
deserves undoubtedly a special place. His fnding that exposure of dry
phospholipids to an excess of water gives rise to lamellar structures
[5] has opened versatile experimental access to studying the
biophysics and biochemistry of biological phospholipid membranes.
Although during the following 4 decades biological membrane models have
grown in complexity and functionality [6], liposomes are, besides
supported bilayers, membrane nanodiscs, and hybrid membranes, still an
indisputably important tool for membrane b- physicists and biochemists.
In vol. II of this book, the reader will fnd detailed methods for the
use of liposomes in studying a variety of biochemical and biophysical
membrane phenomena concomitant with chapters describing a great palette
of state-of-the-art analytical technologies.
