Magnetosensitive nanocomposites on the basis of monodomain magnetite Fe 3 O 4 /meso-2,3-dimercaptosuccinic acid, Fe 3 O 4 /c-aminopropyltriethoxysilane, Fe 3 O 4 / polyacrylamide, Fe 3 O 4 /hydroxyapatite were synthesized. Size distribution of magnetite nanoparticles in ensemble and their magnetic properties were studied. It has been shown that the magnetization curve of the liquid containing monodomain magnetite has a form that is characteristic for superparamagnetics, and its calculations in the framework of Langeven's paramagnetism theory match satisfactorily to the experimental results. The highest adsorption parameters were observed for magnetosensitive nanocomposites Fe 3 O 4 / polyacrylamide and Fe 3 O 4 /c-aminopropyltriethoxysilane. Prospects of the studied nanostructures for medicobiological and technical applications as adsorbents of cis-dichlorodiammineplatinum were shown.

Core-shell magnetosensitive nanocomposites (NC) based on single-domain magnetite (Fe 3 O 4 , core), with a shell consisting of hydroxyapatite (HA) and cytotoxic drug doxorubicin (DOX) layers have been synthesized. The processes of DOX adsorption on Fe 3 O 4 /HA surface from physiologic solution have been studied. DOX release into saline was found to decrease with growing of its quantity on NC surface. It has been determined that cytotoxic influence and antiproliferative activity of Fe 3 O 4 /HA/DOX NC with respect to Saccharomyces cerevisiae cells are characteristic for interaction of these cells with a free form of doxorubicin. Magnetic liquids containing Fe 3 O 4 /HA/ DOX NC stabilized by sodium oleate and polyethylene glycol were prepared and investigated. It is shown that using the ensemble of Fe 3 O 4 carriers as a superparamagnetic probe, the Langevin's paramagnetism theory, and the values of density of nanocomposite constituents, one can evaluate the size parameters of their shell, which has been corroborated by independent measurements of specific surface area of nanostructures and kinetic stability of the corresponding magnetic liquids. The obtained results may be useful for development and optimization of novel forms of magnetocarried medical remedies of targeted delivery and adsorbents based on nanocomposites of superparamagnetic core-shell type with multilevel nanoarchitecture, as well as for determination and control of the size parameters of its components.

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