Microcapsules Based on Pickering Emulsion and Polyelectrolyte Layers: Biomedical Applications

Microcapsules with shells of natural silica nanoparticles are obtained based on the Pickering emulsion and polyelectrolyte layers of chitosan and alginate. The stable emulsions are created by the stabilization of dodecane drops with a mixture of nanoparticles and a cationic surface active substance (SAS) of cetyl trimethylammonium bromide. Polyelectrolyte layers are applied to the surface of drops in the dispersion phase of the emulsion by layer-by-layer adsorption. The drop size is found to depend on the SAS concentration. It is also found that polyelectrolyte layers affected the mechanical stability of the capsule. This stability was higher in the case of gelation of the alginate shell layer with calcium ions. The optimal conditions to create capsules are 10(-3) M cetyl trimethylammonium bromide used for the stabilization of the Pickering emulsion based on natural silica and the subsequent application of the shell consists of chitosan/calcium alginate/chitosan. These procedures result in mechanically stable capsules that are, on average, 6 m in diameter.