Preparation and Properties of Magnetic Composites γ-Fe2O3/SiO2/Aptamer(FAS9) for Magnetic Resonance Hyperthermia

Stolyar, S.V., Li, O.A., Nikolaeva, E.D., (...), Volochaev, M.N., Mokhov, A.A.// Physics of Metals and Metallography//

Powders of maghemite γ-Fe2O3 with an average diameter of 8 nm, γ-Fe2O3/SiO2 composites with an agglomerate diameter of about 50 nm and a size of interspersed γ-Fe2O3 particles of 6 nm, and γ‑Fe2O3/SiO2/aptamer(FAS9) composites were synthesized by chemical deposition. Mössbauer spectra were measured, the static and dynamic magnetic properties of the powders were studied, and the coercive force was determined, which decreases from 14 Oe for γ-Fe2O3 powders to 3 Oe for the γ-Fe2O3/SiO2 composite. It is shown that the particle blocking temperature is close to room temperature. The increment of temperature of the powders was measured in the ferromagnetic resonance mode; the temperature of the Fe2O3/SiO2 composite (ΔT ≈ 16°C) turned out to be higher than that of the pure γ-Fe2O3 powder (ΔT ≈ 10°C). It has been experimentally shown that temperature increment ΔT is proportional to the square of the microwave field amplitude. It has been shown that the composition γ-Fe2O3/SiO2/aptamer FAS9 is able to effectively bind to tumor cells, and FMR hyperthermia leads to a decrease in the viability of tumor cells.