Multiliposomal containers obtained by the successive adsorption of cationic polypeptide poly(L-lysine) and anionic liposomes on the surface of anionic magnetic microgels—the products of γ-Fe 2 O 3 (maghemite) synthesis in the matrix of natural anionic polysaccharide—the mixed Na/Ca salt of alginic acid—are presented. The composition and morphology of magneto-sensitive microgels are studied by X-ray analysis, FTIR spectroscopy, Mössbauer spectroscopy, magnetometry, and transmission electron microscopy. The size of particles of multiliposomal containers with the ultimate liposome content in the physiological solution is about 400 nm. They are not cytotoxic up to a poly(L-lysine) concentration of 600 μM. It is shown that these objects filled with antitumor antibiotic—doxorubicin—are able to move in a suspension under application of an external magnetic field with the integrity of liposomes in the container being preserved. The obtained containers are promising for the controlled delivery of bioactive substances (drugs).

A synthetic procedure is described for preparation of magneto-sensitive nanocomposites from maghemite nanoparticles and a natural polysaccharide, sodium alginate cross-linked with calcium ions. With this procedure, a series of nanocomposites was synthesized and characterized by spectrophotometry, transmission electron microscopy, X-ray diffraction, Mössbauer spectroscopy, Fourier transform IR-spectroscopy and magnetometry with the following main conclusions: (a) The nanocomposites retain their solubility in water unless the iron content exceeds 18.1±0.2 wt%. (b) Only γ-Fe2O3 nanoparticles are included in the nanocomposite. (c) Size of nanoparticles lies within a 4–20 nm range with a dominant diameter of 7±1 nm. (d) Maghemite nanoparticles bind to the alginate matrix via formation of electrostatic and coordination contacts between the surface Fe3+ maghemite ions and functional alginate groups. (e) The nanocomposites exhibit properties which are characteristic for soft magnetic materials since they have a low coercive force. (f) Magnetic characteristics of the nanocomposites, saturation magnetization and residual magnetization, are effectively controlled by the maghemite content. (g) An external magnetic field causes the nanocomposites to move in an aqueous dispersion.