Magnetically Responsive Polyelectrolyte Nanocapsules

In the past decades nanocapsules gained increasing interest in biomedical applications. They can be used as carriers of the lipophilic, poorly water-soluble, or even water-insoluble drugs. Such carriers can be specifically developed for achieving intelligent drug delivery system. Targeting towards selected pathologically changed tissues/cells would enable delivery of the drug only to the selected tissues. That should not only significantly decrease deleterious side effects, but also may drastically enhance therapy efficiency. Various approaches were proposed to accomplish this goal. The layer-by-layer adsorption of charged species like polyelectrolytes, nanoparticles, proteins, organic molecules, etc. is considered as a convenient method to obtain multilayer nano and microcapsules’ shells on colloidal cores. A polyelectrolyte shell of capsules can be functionalized by magnetic nanoparticles to form  magnetic carrier which could be guided with magnetic field gradients and therefore, could transport the biologically active matters with an optimum therapeutic concentration of the pharmaceuticals to the desired tissue of the organism, while the total dosage remaining unchanged. The aim of this work was to develop the method of preparation of magnetically responsive, loaded nanocapsules based on a liquid core encapsulation by polyelectrolyte (PE) multilayer adsorption. Magnetically responsive drug nano delivery systems were prepared by the sequential adsorption of polyelectrolytes (layer by layer technique) using biocompatible polyelectrolytes (Poly L-lysine as the polycation and Poly Glutamic acid  as the polyanion). The model lipophilic drug, β-carotene, was successfully encapsulated in the liquid core while Fe₃O₄ nanoparticles were embedded into the polyelectrolyte multilayer shell. This magnetically responsive drug nano delivery system may be  a promising platform for future targeted therapies (e.g. cancer) or other biomedical applications (e.g. separation systems, diagnostics).