The growth of bilayer defects and the induction of interdigitated domains in the lipid-loss process of supported phospholipid bilayers.

The lipid-loss process has been studied with in situ atomic force microscopy (AFM) at six different temperatures for supported dipalmitoylphosphatidylcholine (DPPC) bilayers. A typical structural characteristic is the creation and the growth of bilayer defects as lipid molecules are lost from the bilayer. The rate of the lipid loss has an Arrhenius behavior, with an activation energy of 37 kT, where kT is the thermal energy at room temperature. For the lipid-loss processes at temperatures above 45 degrees C, interdigitated membrane domains are induced and are mostly in contact with some bilayer defects. These domains disappear at the increase of the area of bilayer defects. Possible mechanisms of these phenomena are discussed.