Instituto de Investigacións Tecnolóxicas and Departamento de Física Aplicada, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
Department of Physics, University of York, York YO10 5DD, UK.
Soft Matter. 2016 Nov 4;12(43):8815-8818. doi: 10.1039/c6sm01910b.
In the magnetic fluid hyperthermia (MFH) research field, it is usually assumed that achieving a uniform temperature enhancement (ΔT) of the entire tumour is a key-point for treatment. However, various experimental works reported successful cell apoptosis via MFH without a noticeable ΔT of the system. A possible explanation of the success of these negligible-ΔT experiments is that a local ΔT restricted to the particle nanoenvironment (i.e. with no significant effect on the global temperature T) could be enough to trigger cell death. Shedding light on such a possibility requires accurate knowledge of heat dissipation at the local level in relation to the usually investigated global (average) one. Since size polydispersity is inherent to all synthesis techniques and the heat released is proportional to the particle size, heat dissipation spots with different performances - and thus different effects on the cells - will likely exist in every sample. In this work we aim for a double objective: (1) to emphasize the necessity to distinguish between the total dissipated heat and hyperthermia effectiveness, and (2) to suggest a theoretical approach on how to select, for a given size polydispersity, a more adequate average size so that most of the particles dissipate within a desired heating power range. The results are reported in terms of FeO nanoparticles as a representative example.
在磁流体热疗（MFH）研究领域，通常认为实现整个肿瘤的均匀温度升高（ΔT）是治疗的关键。然而，各种实验工作表明，通过 MFH 可以实现成功的细胞凋亡，而系统没有明显的ΔT。这些微不足道的ΔT 实验成功的一个可能解释是，局部 ΔT 限制在颗粒纳米环境中（即对全局温度 T 没有显著影响）足以引发细胞死亡。要阐明这种可能性，需要准确了解与通常研究的全局（平均）相比，局部水平的热耗散情况。由于所有合成技术都存在尺寸多分散性，并且释放的热量与颗粒尺寸成正比，因此在每个样品中都可能存在具有不同性能的散热点——从而对细胞产生不同的影响。在这项工作中，我们的目标是双重的：（1）强调有必要区分总耗散热量和热疗效果，（2）提出一种理论方法，说明如何选择给定的尺寸多分散性，以获得更合适的平均尺寸，从而使大多数颗粒在所需的加热功率范围内进行散热。研究结果以 FeO 纳米颗粒为例进行了报道。
