Micellization and solubilization of phospholipids by surfactants

Phospholipids comprise the major component that defines biological membranes. Yet these amphiphilic molecules exist as liquid crystals when they are dispersed in water. Surfactants which form micelles in aqueous solution are quite useful in solubilizing the phospholipids by converting them into mixed micelles. Phospholipids containing short-chain fatty acids have also been chemically synthesized and these form micelles themselves without added surfactants. Below their cmc, monomers of these synthetic phospholipids can be co-micellized with surfactants. The solubilization of natural phospholipids and the micellization of synthetic phospholipids as well as their co-micellization by surfactants will be discussed. Emphasis will be placed on nonionic surfactants where the formation of micelles and mixed micelles with phospholipids has been well studied.