ИСТИНА

Thedevelopment of new nanocompositematerials with magnetically adjustable set of properties isof great importance because of great potentialof their use in biomedicine. The magnetic properties of nanoparticles determine their applicationsas: 1) contrast agents in magnetic resonance imagingstudies; 2) compositionsfor hyperthermiatreatment of lesions in the body, and 3) the magnetic component of compositions for targeted drug delivery. Thepolymer matrix of the composite materials must provide stabilization of nanoparticles by preventing their aggregation and adhesion, solubility in physiological environments. We presentpolymer composites of well definedmaghemite nanoparticles and biocompatible anionic polysaccharide, carboxymethylcellulose. EXPERIMENTALSTUDYSeries of nanocomposites were synthesized at room temperature by treatment ofalkaline solution Fe(NH4)2(SO4)2x 6H2Owithsodium hypophosphite in the presence of polymer at various ratios of components. Maghemite formation was confirmed by X-ray diffraction and Möessbauer spectroscopy. To visualize and determine the size of the inorganic particles included in the composite transmission electron microscopy (TEM) was used. The nature of the interaction of macromolecules withmaghemite nanoparticles was studied by IR spectroscopy. Magnetic properties of nanocomposites maghemite–carboxymethylcellulisewereinvestigated by meansof magnetometry.RESULTSAND DISCUSSIONThe proposed method of synthesis allowsoneto obtain water-soluble materials with controlled content of inorganic magnetic phase. Withthis techniquefine definedmaghemite nanoparticles with a narrow size distributionare formed. One of the major advantages of the proposed method is normal conditions of the synthesis. The role of polysaccharide macromoleculesmatrixis to restrict the growth and prevent the aggregation of forming magnetic nanoparticles. The average size of theresulted nanoparticles inclusions were15nm. The crystallographydata has confirmed the maghemite structure of iron oxide nanoparticles. It wasshown that the inorganic particles werebound to the polymer matrix by electrostatic interaction and byformation of coordination complexes. Magnetic properties of the obtained nanocomposites (saturation magnetization, residual magnetization, coercive force) were shown to dependon the maghemitecontent. Being dissolved in water nanocomposites formedaggregation-stable dispersions that weresensitive to the action of an external magnetic field. Stability against aggregation was ensured by overall negative surface charge of particles in the nanocomposite.CONCLUSIONAn originalmethod for producing biocompatible nanocomposite materials with chemically stable maghemitewas proposed. The proportion of the magnetic phase in the composite magemitte–carboxymethylcellulosecould be controlled bycomponent ratio in the initial reactive mixture. The high negative charge ofthe resultedcomposites determines the colloid their stability in water-salt media and opens the gates for their further usage inproducingmagnetically controlled drugsand diagnostic ensembles.ACKNOWLEDGMENTSThis work was supported by Russian Foundation for Basic Research (project 17-03-00433)