Fuel-Free Locomotion of Janus Motors: Magnetically Induced Thermophoresis
Fuel-Free Locomotion of Janus Motors: Magnetically Induced Thermophoresis
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DOI：
10.1021/nn305726m
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发表时间：
2013-02-01
期刊：
影响因子：
17.1
通讯作者：
Cuniberti, Gianaurelio
中科院分区：
文献类型：
--
作者：
Baraban, Larysa;Streubel, Robert;Cuniberti, Gianaurelio
我们提出了由磁感应热泳驱动的磁性球形 Janus 电机的无燃料运动，即由于局部温度梯度而在任何液体介质中物体的自扩散推进。在这种方法中，应用交流磁场通过加热颗粒的磁帽来诱导物体的热泳运动，同时使用附加的直流磁场来定向 Janus 电机并在长时间范围内引导它们的运动。由于超薄 100 nm 厚坡莫合金（Py、Fe19Ni81 合金）磁性薄膜的特殊特性，可在 Janus 电机的帽结构中形成拓扑稳定的磁涡流状态，从而实现对运动的完全控制。此处实现的磁感应热泳运动不需要意味着有毒试剂的催化化学反应。在这方面，我们解决并成功解决了人工电机领域的主要缺点之一，即完全受控并保持生物相容性。因此，我们的方法对于生物技术体外测定甚至体内操作都很有吸引力，因为 Janus 电机的功能具有低毒性；它不依赖于溶液中燃料分子的存在。此外，与之前提出的使用激光的光感应加热相比，所建议的磁交流激励更优越，因为它不需要透明封装。
We present fuel-free locomotion of magnetic spherical Janus motors driven by magnetically induced thermophoresis a self diffusive propulsion of an object in any liquid media due to a local temperature gradient. Within this approach an ac magnetic field is applied to induce thermophoretic motion of the objects via heating a magnetic cap of the particles, while an additional dc magnetic field is used to orient Janus motors and guide their motion on a long time scale. Full control over the motion is achieved due to specific properties of ultrathin 100-nm-thick Permalloy (Py, Fe19Ni81 alloys) magnetic films resulting in a topologically stable magnetic vortex state in the cap structure of Janus motors. Realized here magnetically induced thermophoretic locomotion does not require catalytic chemical reactions that imply toxic reagents. In this respect, we addressed and successfully solved one of the main shortcomings in the field of artificial motors, namely being fully controlled and remain biocompatible. Therefore, our approach is attractive for biotechnological in vitro assays and even in vivo operations, since the functioning of Janus motors offers low toxicity; it is not dependent on the presence of the fuel molecules in solution. Furthermore, the suggested magnetic ac excitation is superior compared to the previously proposed optically induced heating using lasers as it does not require transparent packaging.