Faculty of Physics, M. V. Lomonosov Moscow State University, 119991 Moscow, Russia.
Institute of Biological and Medical Imaging, Helmholtz Zentrum München, 85764 Neuherberg, Germany and Chair of Biological Imaging, Technische Universität München, 80333 Munich, Germany.
Phys Chem Chem Phys. 2017 May 10;19(18):11510-11517. doi: 10.1039/c7cp00728k.
The development of suitable contrast agents can significantly enhance the efficiency of modern imaging and treatment techniques, such as thermoacoustic (TA) tomography and radio-frequency (RF) hyperthermia of cancer. Here, we examine the heating of aqueous suspensions of silicon (Si) and gold (Au) nanoparticles (NPs) under RF irradiation in the MHz frequency range. The heating rate of aqueous suspensions of Si NPs exhibited non-monotonic dependency on the electrical conductivity of the suspension. The experimental results were explained by the mathematical model considering oscillating solvated ions as the main source of Joule heating. These ions could be the product of the dissolution of Si NPs or organic coating of Au NPs. Thus, the ions governed the conductivity of the suspensions, which in turn governs both the heating rate and the near-field RF TA response. The model predicted the contrast in different tissues taking into account both Joule heating and dielectric losses.
合适的对比剂的发展可以显著提高现代成像和治疗技术的效率，例如热声（TA）断层扫描和癌症的射频（RF）热疗。在这里，我们研究了在 MHz 频率范围内 RF 辐照下硅（Si）和金（Au）纳米颗粒（NPs）水悬浮液的加热。Si NPs 水悬浮液的加热速率与悬浮液的电导率呈非单调依赖性。实验结果通过考虑作为焦耳加热主要来源的振荡溶剂化离子的数学模型来解释。这些离子可能是 Si NPs 溶解或 Au NPs 有机涂层的产物。因此，离子控制悬浮液的电导率，这反过来又控制加热速率和近场 RF TA 响应。该模型考虑了焦耳加热和介电损耗，预测了不同组织之间的对比度。
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