Highly Efficient Freestyle Magnetic Nanoswimmer
Highly Efficient Freestyle Magnetic Nanoswimmer
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DOI：
10.1021/acs.nanolett.7b02383
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发表时间：
2017-08-01
期刊：
影响因子：
10.8
通讯作者：
Wang, Joseph
中科院分区：
文献类型：
--
作者：
Li, Tianlong;Li, Jinxing;Wang, Joseph
天然微生物独特的游泳策略激发了最近由人造螺旋或柔性鞭毛驱动的磁性微型/纳米机器人的发展。然而，随着具有独特几何结构的人造纳米微球的开发，探索新的潜在动力学优化模式至关重要。例如，自由泳是人类竞技游泳中最有效的泳姿。在这里，我们报道了一种新型的磁性纳米机器人，一种对称的多连双臂纳米机器人，能够在低雷诺数下有效地进行自由泳。实验观测与理论预测的良好一致性表明，双臂纳米机器人强大的自由式推进是由于纳米机器人在磁场和粘性力的共同作用下发生的同步振荡变形。首次证明了非平面推进步态可以由平面振荡磁场提供能量，这种非平面推进步态是由两个磁臂相互配合的“自由式”行程产生的。这些双臂纳米机器人能够以每秒12个身体长度的强大推进力，以及按需调节速度和远程导航。非手性磁性臂连续摆动驱动的非平面推进步态比普通手性纳米螺旋游泳者的步态效率更高。这种新的游泳机制及其诱人的性能为设计用于纳米级生物医学操作的远程驱动纳米机器人开辟了新的可能性。
The unique swimming strategies of natural microorganisms have inspired recent development of magnetic micro/nanorobots powered by artificial helical or flexible flagella. However, as artificial nanoswimmers with unique geometries are being developed, it is critical to explore new potential modes for kinetic optimization. For example, the freestyle stroke is the most efficient of the competitive swimming strokes for humans. Here we report a new type of magnetic nanorobot, a symmetric multilinked two-arm nanoswimmer, capable of efficient "freestyle" swimming at low Reynolds numbers. Excellent agreement between the experimental observations and theoretical predictions indicates that the powerful "freestyle" propulsion of the two-arm nanorobot is attributed to synchronized oscillatory deformations of the nanorobot under the combined action of magnetic field and viscous forces. It is demonstrated for the first time that the nonplanar propulsion gait due to the cooperative "freestyle" stroke of the two magnetic arms can be powered by a plane oscillatory magnetic field. These two-arm nanorobots are capable of a powerful propulsion up to 12 body lengths per second, along with on-demand speed regulation and remote navigation. Furthermore, the nonplanar propulsion gait powered by the consecutive swinging of the achiral magnetic arms is more efficient than that of common chiral nanohelical swimmers. This new swimming mechanism and its attractive performance opens new possibilities in designing remotely actuated nanorobots for biomedical operation at the nanoscale.