Matrix effect in oleate micelles-vesicles transformation.

It is accepted by many authors that the formation of closed molecular structures is a key step in the evolution of life. Oleate vesicles represent a good model system in this framework due to the fact that they self-assemble spontaneously and that fatty acids are considered as possible prebiotic structures. In this contribution, we will focus the attention on the transition from oleate micelles to oleic acid/oleate vesicles induced by a pH change. This transformation is strongly influenced by the presence of pre-formed vesicles. We called this phenomenon the matrix effect. The influence of pre-added POPC liposomes (POPC = 1-palmitoyl-2-oleoyl-sn-glycerol-3-phosphocholine) and oleic acid/oleate vesicles on the process rate and on the final size distribution will be discussed elucidating the main differences between these two systems.