Vesicle is a kind of closed bimolecular layer structure aggregate in the arrangement of hydrophobic groups to hydrophobic groups of surfactant molecules. The oriented bilayer of surfactants forms the shell of vesicle, and its interior is aqueous phase.
Vesicles can be divided into single compartment vesicle and multi-compartment vesicle.
Multi-compartment vesicles are composed of multiple oriented bilayers with the same spherical center, and there is aqueous phase between the layers and internal core.
The shape of vesicles is mostly spherical, ellipsoidal or oblate.
The size of vesicles is roughly in the colloidal range, which is an unstable dispersion system.
Vesicle formed by phospholipids is usually called liposome.