The relevance of Brownian relaxation as power absorption mechanism in Magnetic Hyperthermia
The relevance of Brownian relaxation as power absorption mechanism in Magnetic Hyperthermia
复制标题
DOI：
10.1038/s41598-019-40341-y
复制
发表时间：
2019-03-08
影响因子：
4.6
通讯作者：
Goya, Gerardo F.
中科院分区：
文献类型：
--
作者：
Torres, Teobaldo E.;Lima Jr, Enio;Goya, Gerardo F.
线性响应理论 (LRT) 是一种被广泛接受的框架，用于分析磁流体热疗中磁性纳米颗粒的功率吸收。其有效性仅限于低应用场和/或高度各向异性磁性纳米粒子。在这里，我们对不同平均尺寸和不同粘性介质中的高各向异性钴铁氧体（CoFe2O4）磁性纳米颗粒的比功率吸收进行了系统的实验分析和数值计算。布朗弛豫作为这些颗粒中磁损耗的起源的主导地位被确立，并且比功率吸收（SPA）随载液粘度的变化与 LRT 近似一致。粘度对 SPA 的影响与体外和体内实验期间加热细胞内介质的 MNP 的设计相关。本文结合数值和实验分析揭示了高度各向异性 MNP 不适合磁热疗的潜在机制。
The Linear Response Theory (LRT) is a widely accepted framework to analyze the power absorption of magnetic nanoparticles for magnetic fluid hyperthermia. Its validity is restricted to low applied fields and/or to highly anisotropic magnetic nanoparticles. Here, we present a systematic experimental analysis and numerical calculations of the specific power absorption for highly anisotropic cobalt ferrite (CoFe2O4) magnetic nanoparticles with different average sizes and in different viscous media. The predominance of Brownian relaxation as the origin of the magnetic losses in these particles is established, and the changes of the Specific Power Absorption (SPA) with the viscosity of the carrier liquid are consistent with the LRT approximation. The impact of viscosity on SPA is relevant for the design of MNPs to heat the intracellular medium during in vitro and in vivo experiments. The combined numerical and experimental analyses presented here shed light on the underlying mechanisms that make highly anisotropic MNPs unsuitable for magnetic hyperthermia.