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

https://doi.org/10.1134/S0031918X23601439

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.