New manganite-based mediators for self-controlled magnetic hyperthermia

Keywords:
magnetic hyperthermia, manganites, nanopowders, smart materials

Abstract:
In order to develop alternative magnetic mediator materials, RF heating properties of several doped La manganites were studied. Aqueous suspensions of La-Sr, La-Ag and La-Na manganite powders with Tc = 320-340 K, obtained by freeze drying synthesis method, demonstrated the efficient RF absorption at room temperature. At the temperatures approaching Tc a steep decrease of the heating rate was observed followed by the temperature stabilization. RF absorption intensity of several manganite powders with crystallite size ~ 0.1 microns was comparable with that one of traditional ferrofluids, demonstrating little or no dependence on the particle agglomeration. Essential feature of these materials is systematic dependence of Tc on the La/Me ratio that makes possible fine and reproducible control of the final temperature. Apart from other kinds of magnetic mediators, manganites demonstrated rather limited dependence of the final temperature on the concentration of mediator particles. This feature prevents possible local overheating, occurred in usual Fe3O4-based ferrofluids, and allows to consider doped La manganites as a new class of smart mediators for magnetic hyperthermia and other biomedical applications demanding contactless heating with autonomous temperature control.

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Nanotech 2006 Conference Program Abstract