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
Resonancias Magnéticas, Comision Nacional de Energia Atomica - Centro Atomico Bariloche, San Carlos de Bariloche, Río Negro, ARGENTINA.
Centro Atomico Bariloche, Bariloche, ARGENTINA.
Nanotechnology. 2020 Oct 21. doi: 10.1088/1361-6528/abc386.
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 applications. To pursue this goal, Fe3O4/ZnxCo1-xFe2O4 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 at% 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 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 .
在这项工作中，展示了一种精确的方法，通过调节核/壳双磁性纳米颗粒中的奈尔弛豫时间，来优化高粘度磁性胶体中的热生成，用于磁流体热疗应用。为实现这一目标，合成了平均核直径为8.5 nm的Fe3O4/ZnxCo1-xFe2O4核/壳纳米颗粒，包裹在厚度约为1.1 nm的壳中，其中锌原子比（Zn/(Zn+Co)原子百分比）从33原子百分比变化到68原子百分比。磁性测量结果与核相和壳相之间的刚性界面耦合一致，当锌浓度增加时，有效磁各向异性系统地降低，而饱和磁化强度没有显著变化。将0.1 wt%的这些颗粒分散在水、DMEM（杜尔贝科改良伊格尔最低基本培养基）和高粘度黄油油中进行磁流体热疗实验，当实验在571 kHz和200 Oe下进行时，产生了高达150 W/g的大比损耗功率（SLP）。通过调节壳的组成优化了SLP，在中间锌浓度时显示出最大值。这项研究展示了一种方法，对于那些需要更小粒径的生物医学应用，可在诸如细胞质溶胶等粘性介质中最大化热生成。
