A schematic representation of the monolayer behavior of a complex lipid mixture with compression. (a) Upon lateral compression, saturated and unsaturated phospholipids as well as NLs (cholesterol, triglycerides) become unstable at very high surface density and form bilayer folds. The bilayer folds can bend to form semi-vesicles. (b) A schematic representation of differences in lipid arrangement on the subphase and on solid substrate between sensitive and resistant cell membrane lipids. Lipids extracted from sensitive cells form vesicles, which are uniform and have similar interfacial characteristics, whereas in resistant cells, because of the higher number of lipid species, vesicles with different interfacial characteristics are formed. Domains are formed due to differences in interfacial characteristics, which arise due to differences in the head group, a hydrophobic chain length of lipids in different vesicles.