Spontaneously formed semipermeable organic-inorganic hybrid vesicles permitting molecular weight selective transmembrane passage.

Semipermeable organic-inorganic hybrid vesicles coated with a siloxane surface were spontaneously formed by simple dispersion of an organoalkoxysilane lipid in water. The hybrid vesicles allow the permeation of hydrophilic small molecules across the membrane without an introduction of a pore-forming protein.