Magnetically Controlled Hyaluronic Acid-Maghemite Nanocomposites with Embedded Doxorubicin.

The controllable delivery of drugs is a key task of pharmacology. For this purpose, a series of polymer composites was synthesized via the cross-linking of hyaluronate and a hyaluronate/polyacrylate mixture with Fe2O3 nanoparticles. The cross-linking imparts magnetic properties to the composites, which are more pronounced for the ternary hyaluronate/polyacrylate/γ-Fe2O3 composites compared with the binary hyaluronate/Fe2O3 composites. When dispersed in water, the composites produce microsized hydrogel particles. Circulation of the ternary microgels in an aqueous solution at a speed of 1.84 cm/s can be stopped using a permanent external magnet with a magnetic flux density of 400 T. The composite hydrogels can absorb the antitumor antibiotic doxorubicin (Dox); the resulting constructs show their cytotoxicity to tumor cells to be comparable to the cytotoxicity of Dox itself. The addition of the hyaluronidase enzyme induces degradation of the binary and ternary microgels down to smaller particles. This study presents prospectives for the preparation of magnetically controlled biodegradable polymer carriers for the encapsulation of bioactive substances.

One-Step Low Temperature Synthesis of CeO2 Nanoparticles Stabilized by Carboxymethylcellulose.

An elegant method of one-pot reaction at room temperature for the synthesis of nanocomposites consisting of cerium containing nanoparticles stabilized by carboxymethyl cellulose (CMC) macromolecules was introduced. The characterization of the nanocomposites was carried out with a combination of microscopy, XRD, and IR spectroscopy analysis. The type of crystal structure of inorganic nanoparticles corresponding to CeO2 was determined and the mechanism of nanoparticle formation was suggested. It was demonstrated that the size and shape of the nanoparticles in the resulting nanocomposites does not depend on the ratio of the initial reagents. Spherical particles with a mean diameter 2-3 nm of were obtained in different reaction mixtures with a mass fraction of cerium from 6.4 to 14.1%. The scheme of the dual stabilization of CeO2 nanoparticles with carboxylate and hydroxyl groups of CMC was proposed. These findings demonstrate that the suggested easily reproducible technique is promising for the large-scale development of nanoceria-containing materials.

Mössbauer, Nuclear Forward Scattering, and Raman Spectroscopic Approaches in the Investigation of Bioinduced Transformations of Mixed-Valence Antimony Oxide.

Mössbauer spectroscopy, nuclear forward scattering, and Raman spectroscopy were applied to study redox transformations of the synthesized mixed-valence (III/V) antimony oxide. The transformations were induced by a culture of a hyperthermophilic archaeon of the genus Pyrobaculum. The applied methods allowed us to reveal the minor decrease of ca. 11.0 ± 1.2% of the antimony(V) content of the mixed-valence oxide with the concomitant increase of antimony(III). The method sensitivities for the quantitative assessment of the Sb(III/V) ratio have been considered.