Adjusting the Néel relaxation time of Fe3O4/ZnxCo1-xFe2O4 core/shell nanoparticles for optimal heat generation in magnetic hyperthermia

FABRIS, FERNANDO; LOHR, JAVIER HERNÁN; LIMA, ENIO; DE ALMEIDA, ADRIELE APARECIDA; TROIANI, HORACIO; RODRÍGUEZ, LUIS M.; VÁSQUEZ MANSILLA, MARCELO; AGUIRRE, MYRIAM; GOYA, GERARDO FABIAN; RINALDI, DANIELE; GHIRRI, ALBERTO; PEDDIS, DAVIDE; FIORANI, DINO; ZYSLER, ROBERTO D; DE BIASI, EMILIO; WINKLER, ELIN

NANOTECHNOLOGY

IOP PUBLISHING LTD

Año: 2020

0957-4484

In this work it is shown a precise way to optimize the heat generation inhigh viscosity magnetic colloids, by adjusting the Néel relaxation time incore/shell bimagnetic nanoparticles, for Magnetic Fluid Hyperthermiaapplications. To pursue this goal, Fe3O4/ZnxCo1-xFe2O4 core/shellnanoparticles were synthesized with 8.5 nm mean core diameter,encapsulated in a shell of ~1.1 nm of thickness, where the Zn atomic ratio (Zn/(Zn+Co) at%) changes from 33 at% to 68 at%. The magneticmeasurements are consistent with a rigid interface coupling between thecore and shell phases, where the effective magnetic anisotropysystematically decreases when the Zn concentration increases, without asignificant change of the saturation magnetization. Experiments of magnetic fluid hyperthermia of 0.1 wt% of these particles dispersed in water, DMEM(Dulbecco modified Eagles minimal essential medium) and a high viscosity butter oil, result in a large specific loss power (SLP), up to 150 W/g, when the experiments are performed at 571 kHz and 200 Oe. The SLP was optimized adjusting the shell composition, showing a maximum for intermediate Zn concentration. This study shows a way to maximize the heat generation in viscous media like cytosol, for those biomedical applications that requiere smaller particle sizes.