Self-assembly of robotic micro- and nanoswimmers using magnetic nanoparticles
Self-assembly of robotic micro- and nanoswimmers using magnetic nanoparticles
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DOI：
10.1007/s11051-014-2737-z
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发表时间：
2015-03-17
影响因子：
2.5
通讯作者：
Kim, Min Jun
中科院分区：
文献类型：
--
作者：
Cheang, U. Kei;Kim, Min Jun
微米和纳米级的机器人游泳者非常有希望通过在极小的尺度上提供高精度来显著提高颗粒药物递送的性能。在这里，我们将介绍使用纳米粒子的自组装和通过磁场控制制造的微米和纳米游泳者。纳米粒子在磁化作用下自排列成平行链。游泳者在旋转磁场下表现出柔性，从而在变形时产生手性结构，从而具有在低雷诺数下进行非往复运动的先决条件。游泳者使用由近似亥姆霍兹线圈提供的外部旋转磁场无线致动。通过控制悬浮的磁性纳米颗粒的浓度，可以将游泳者调制成不同的大小。纳米尺度的游泳者在很大程度上受到布朗运动的影响，正如从他们的颠簸轨迹所观察到的那样。微泳者大约大三倍，不太容易受到布朗运动的影响。在本文中，我们展示了响应方向控制的微型和纳米游泳者，并比较各自的扩散率和轨迹，以表征布朗扰动对小型和大型游泳者的运动的影响。然后，我们进行了模拟，包括布朗运动的随机性质的磁性游泳运动模型。
Micro- and nanoscale robotic swimmers are very promising to significantly enhance the performance of particulate drug delivery by providing high accuracy at extremely small scales. Here, we introduce micro- and nanoswimmers fabricated using self-assembly of nanoparticles and control via magnetic fields. Nanoparticles self-align into parallel chains under magnetization. The swimmers exhibit flexibility under a rotating magnetic field resulting in chiral structures upon deformation, thereby having the prerequisite for non-reciprocal motion to move about at low Reynolds number. The swimmers are actuated wirelessly using an external rotating magnetic field supplied by approximate Helmholtz coils. By controlling the concentration of the suspended magnetic nanoparticles, the swimmers can be modulated into different sizes. Nanoscale swimmers are largely influenced by Brownian motion, as observed from their jerky trajectories. The microswimmers, which are roughly three times larger, are less vulnerable to the effects from Brownian motion. In this paper, we demonstrate responsive directional control of micro- and nanoswimmers and compare their respective diffusivities and trajectories to characterize the implications of Brownian disturbance on the motions of small and large swimmers. We then performed a simulation using a kinematic model for the magnetic swimmers including the stochastic nature of Brownian motion.