Adjusting the Néel relaxation time of Fe3O4/ZnxCo1−xFe2O4 core/shell nanoparticles for optimal heat generation in magnetic hyperthermia. (18th November 2020)

• Record Type: Journal Article
• Authors: Fabris, Fernando; Lohr, Javier; Lima, Enio; de Almeida, Adriele Aparecida; Troiani, Horacio E; Rodríguez, Luis M; Vásquez Mansilla, Marcelo; Aguirre, Myriam H; Goya, Gerardo F; Rinaldi, Daniele; Ghirri, Alberto; Peddis, Davide; Fiorani, Dino; Zysler, Roberto D; De Biasi, Emilio; Winkler, Elin L
• Is Part Of: Nanotechnology. Volume 32:Number 6(2021)
• Publication Date: 2020-11-18
• Subjects: core/shell nanoparticles -- magnetic fluid hyperthermia -- Néel relaxation time; Nanotechnology -- Periodicals; Nanotechnology -- Periodicals; Nanotechnology; Publications périodiques; Nanotechnologies; Periodicals; 620.5
• DOI: 10.1088/1361-6528/abc386
• Languages: English
• ISSNs: 0957-4484

Abstract

Abstract: In this work it is shown a precise way to optimize the heat generation in high viscosity magnetic colloids, by adjusting the Néel relaxation time in core/shell bimagnetic nanoparticles, for magnetic fluid hyperthermia (MFH) applications. To pursue this goal, Fe3 O4 /Zn x Co1− x Fe2 O4 core/shell nanoparticles 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 to 68 at%. The magnetic measurements are consistent with a rigid interface coupling between the core and shell phases, where the effective magnetic anisotropy systematically decreases when the Zn concentration increases, without a significant change of the saturation magnetization. Experiments of MFH of 0.1 wt% of these particles dispersed in water, in 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 −1, 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 require smaller particle sizes.