Department of Physics and Astronomy, University of Georgia, Athens, GA 30602, USA.
Soft Matter. 2017 May 24;13(20):3750-3759. doi: 10.1039/c7sm00488e.
It is discovered that a non-uniform alternating magnetic field can induce a translational motion of an anisotropic magnetic particle or cluster near a surface. Unlike a permanent magnet pulling a magnetic particle, the particle moves away from the magnetic source with a periodic fluctuation in its trajectory that varies with a frequency that is twice that of the field frequency. The moving speed can be tuned by varying the magnetic field strength and gradient, its alternating frequency, and the particle size. A hydrodynamic model is developed that can qualitatively explain all of the phenomena observed. Such a simple particle manipulation method has a great potential in applications such as cell biology and microfluidics.
研究发现，非均匀交变磁场可以诱导各向异性磁颗粒或磁团簇在表面附近产生平移运动。与永磁体吸引磁颗粒不同，颗粒在其轨迹上以两倍于磁场频率的频率进行周期性波动，从而远离磁源。通过改变磁场强度和梯度、交变频率以及颗粒尺寸，可以调节运动速度。本文提出了一个可以定性解释所观察到的所有现象的流体动力学模型。这种简单的粒子操控方法在细胞生物学和微流控等应用中具有很大的潜力。
