Edge Energy
Edge energy is the energy per unit length of a free edge contacting water. This can be thought of as the work needed to create a hole in the bilayer of unit length L. The origin of this energy is the fact that creating such an interface exposes some of the lipid tails to water, which is unfavorable. is also an important parameter in biological phenomena as it regulates the self-healing properties of the bilayer following electroporation or mechanical perforation of the cell membrane. Unfortunately, this property is both difficult to measure experimentally and to calculate. One of the major difficulties in calculation is that the structural properties of this edge are not known. The simplest model would be no change in bilayer orientation, such that the full length of the tail is exposed. This is a high energy conformation and, to stabilize this edge, it is likely that the some of the lipids rearrange their head groups to point out in a curved boundary. The extent to which this occurs is currently unknown and there is some evidence that both hydrophobic (tails straight) and hydrophilic (heads curved around) pores can coexist.
Read more about this topic: Lipid Bilayer Mechanics
Famous quotes containing the words edge and/or energy:
“The self-consciousness of Pine Ridge manifests itself at the village’s edge in such signs as “Drive Keerful,” “Don’t Hit Our Young ‘uns,” and “You-all Hurry Back”Mlocutions which nearly all Arkansas hill people use daily but would never dream of putting in print.”
—Administration in the State of Arka, U.S. public relief program (1935-1943)
“The tendencies of the times favor the idea of self-government, and leave the individual, for all code, to the rewards and penalties of his own constitution, which work with more energy than we believe, whilst we depend on artificial restraints.”
—Ralph Waldo Emerson (1803–1882)