Hollow phosphorylcholine polymer vesicles prepared by a coaxial electrospray technique

Abstract

Hollow vesicles composed of a phosphorylcholine polymer were prepared using a coaxial electrospray technique and an inorganic microstructured template. An aqueous solution containing calcium chloride and chitosan, and 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer ethanol solution were electrosprayed from coaxial double needles into a phosphate solution to obtain microparticles composed of calcium phosphate (CaP) and chitosan covered with MPC polymer, followed by the removal of CaP/chitosan template to produce novel hollow vesicles composed of MPC polymer. The resulting hollow vesicles had 300–400 μm in diameter. Investigation using fluorescently labeled MPC polymer revealed that the vesicle membrane was composed of MPC polymer. Model substances with relatively high molecular weights (dextran and polymeric microspheres) were readily encapsulated in the hollow vesicles. Microscopic observations of the mobility of encapsulated microspheres inside a hollow vesicle indicated the fluidity of its aqueous interior. Finally, we succeeded in the encapsulation and cultivation of living yeast cells within the vesicles, which demonstrates that this technique can encapsulate a physiologically active substance in the hollow vesicles and maintain its activity.