Magnetic and viscous modes for physical rotation of magnetic nanoparticles in liquid under oscillating magnetic field
Magnetic and viscous modes for physical rotation of magnetic nanoparticles in liquid under oscillating magnetic field
复制标题
振荡磁场下液体中磁性纳米颗粒物理旋转的磁和粘性模式
DOI：
10.1063/5.0010095
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发表时间：
2020
影响因子：
4
通讯作者：
S. Tsukahara
中科院分区：
文献类型：
--
作者：
M. Suwa;A. Uotani;S. Tsukahara
液体中的磁性纳米颗粒（MNP）对交变磁场的响应是复杂的，因为MNP中的磁矩（内旋转）和MNP本身（物理旋转）的旋转运动相互影响。阐明这些旋转行为的机理对于近年来纳米粒子生物应用的成功是十分必要的。然而，物理旋转观测的实验技术一直缺乏。在我们以前的工作中，我们证明了MNP的物理旋转可以从法拉第配置的吸光度变化定量测量。然后，它被揭示，10 nm大小的磁赤铁矿MNP保持在一定程度上与小振荡对齐。这种行为与Usov和Liubimov从他们的数值模拟中提出的“磁模式”一致。在本研究中，我们改进了装置，以测量与Voigt配置的诱导线性二向色性。这种改进增加了约100倍的信噪比，并使我们能够调查的物理旋转的磁铁矿MNP的大小的依赖性。结果表明，较小的MNP（11 nm和13 nm）在磁性模式下旋转。相比之下，最大的MNP（25 nm）的旋转运动与较小的MNP相比具有不同的特征。这些差异可以用Usov和Liubimov也预测的“粘性模式”来解释。此外，我们建议一个无量纲参数作为一个有用的标准，这些模式的过渡。
The response of magnetic nanoparticles (MNPs) in a liquid to an alternating magnetic field is complicated because the rotational motions of both the magnetic moment in the MNP (internal rotation) and the MNP itself (physical rotation) affect each other. It is necessary to elucidate the mechanisms of these rotation behaviors for the success of the recent bio-applications of MNPs. However, the experimental technique for the observation of the physical rotation has been lacking. In our previous work, we demonstrated that the physical rotation of MNPs could be measured quantitatively from the absorbance change with a Faraday configuration. Then, it was revealed that the ten nm-sized maghemite MNP kept aligning to some extent with small oscillation. This behavior is consistent with the “magnetic mode” that Usov and Liubimov proposed from their numerical simulation. In the present study, we improved the apparatus to measure the induced linear dichroism with a Voigt configuration. This improvement increased the signal-to-noise ratio by about 100 times and allowed us to investigate the dependence of the physical rotation on the size of magnetite MNPs. It was shown that smaller MNPs (11 nm and 13 nm) rotated in the magnetic mode. By contrast, the rotational motion of the biggest MNP (25 nm) had different features compared to the smaller ones. These differences can be explained with “viscous mode” that Usov and Liubimov also predicted. Furthermore, we suggest a dimensionless parameter as a useful criterion for the transition of these modes.
影响因子：
10.8
作者：
Yu EY;Bishop M;Zheng B;Ferguson RM;Khandhar AP;Kemp SJ;Krishnan KM;Goodwill PW;Conolly SM
通讯作者：
Conolly SM
影响因子：
12.6
作者：
Zhang, Xiaojuan;Reeves, Daniel B.;Perreard, Irina M.;Kett, Warren C.;Griswold, Karl E.;Gimi, Barjor;Weaver, John B.
通讯作者：
Weaver, John B.