Multilayer capsules with cell-like topology:: Fabrication and spontaneous loading of various substances in aqueous and ethanol solutions

Multilayer microcapsules are fabricated by layer-by-layer assembly of sodium poly(styrene sulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) on porous CaCO3 microparticles, followed by removal of the sacrificial template. Confocal microscopy (CLSM) reveals that the obtained capsules have polyelectrolyte complex cores, which connect with the shells through polyelectrolyte complex fibers (so called cell-like topology). The complex is composed of PSS and PAH bound by electrostatic interaction during the assembly procedure, as evidenced by confocal Raman image. CLSM characterization demonstrates that positively charged rhodamine 6G, neutral Nile red and negatively charged 6-carboxyfluorescein can all be spontaneously encapsulated either in aqueous or in ethanol solution.