Abedini-Nassab Roozbeh, Joh Daniel Y, Van Heest Melissa, Baker Cody, Chilkoti Ashutosh, Murdoch David M, Yellen Benjamin B
Department of Mechanical Engineering and Materials Science, Duke University, Box 90300 Hudson Hall, Durham, NC 27708, USA.
Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, USA.
Adv Funct Mater. 2016 Jun 14;26(22):4026-4034. doi: 10.1002/adfm.201503898. Epub 2015 Dec 7.
We demonstrate magnetophoretic conductor tracks that can transport single magnetized beads and magnetically labeled single cells in a 3-dimensional time-varying magnetic field. The vertical field bias, in addition to the in-plane rotating field, has the advantage of reducing the attraction between particles, which inhibits the formation of particle clusters. However, the inclusion of a vertical field requires the re-design of magnetic track geometries which can transport magnetized objects across the substrate. Following insights from magnetic bubble technology, we found that successful magnetic conductor geometries defined in soft magnetic materials must be composed of alternating sections of positive and negative curvature. In addition to the previously studied magnetic tracks taken from the magnetic bubble literature, a drop-shape pattern was found to be even more adept at transporting small magnetic beads and single cells. Symmetric patterns are shown to achieve bi-directional conduction, whereas asymmetric patterns achieve unidirectional conduction. These designs represent the electrical circuit corollaries of the conductor and diode, respectively. Finally, we demonstrate biological applications in transporting single cells and in the size based separation of magnetic particles.
我们展示了磁泳导体轨道，其能够在三维时变磁场中运输单个磁化珠子和磁标记的单细胞。除了平面内旋转场之外，垂直场偏置具有减少粒子之间吸引力的优点，这种吸引力会抑制粒子簇的形成。然而，包含垂直场需要重新设计能够在基板上运输磁化物体的磁轨道几何形状。根据磁泡技术的见解，我们发现软磁材料中定义的成功磁导体几何形状必须由正负曲率的交替部分组成。除了先前从磁泡文献中研究的磁轨道之外，还发现一种水滴形图案甚至更擅长运输小磁珠和单细胞。对称图案显示可实现双向传导，而非对称图案实现单向传导。这些设计分别代表了导体和二极管的电路推论。最后，我们展示了在运输单细胞以及基于尺寸分离磁性颗粒方面的生物学应用。
