Lipid vesicles as possible intermediates in the origin of life

Lipid vesicles (liposomes) are closed structures in which (at least) one lipid bilayer separates an aqueous inner compartment from the bulk external aqueous medium, as in membranes of contemporary biological cells. Lipid vesicles have therefore been considered as possible cell precursors during the prebiological era on Earth. Recently, it has been shown that lipid vesicles form spontaneously. Furthermore, it has been demonstrated that thermodynamically controlled peptide binding to and controlled polymerization reactions on vesicles are possible, thus leading to an increase in the molecular complexity of lipid vesicles. This may have been relevant during the prebiological evolution. © 1999 Elsevier Science Ltd.