Department of Materials Science and Engineering, Chungnam National University, Daejeon 305-764, South Korea.
Biosens Bioelectron. 2010 Dec 15;26(4):1755-8. doi: 10.1016/j.bios.2010.08.033. Epub 2010 Aug 19.
We demonstrate real time on-chip translocation of bio-functionalized superparamagnetic beads on a silicon surface in a solution using a magnetophoresis technique. The superparamagnetic beads act as biomolecule carriers. Fluorescent-labeled Atto-520 biotin was loaded to streptavidin-coated magnetic beads (Dynabead(®) M-280) by means of ligand-receptor interactions. The magnetic pathways were patterned lithographically such that semi-elliptical Ni(80)Fe(20) elements were arranged sequentially for a few hundred micrometers in length. An external rotating magnetic field was used to drive translational forces on the magnetic beads that were proportional to the product of the field strength and its gradient. The translational force at the curving edge of the pathway element of 6 μm diameter was calculated to be ∼1.2 pN for an applied field of 7.9 kA m(-1). However, the force at the flat edge was calculated to be ∼0.16 pN. The translational force was larger than the drag force and thus allowed the magnetic beads to move in a directional way along the curving edge of the pathway. However, the force was not sufficient to move the beads along the flat edge. The top and bottom curving edge semi-elliptical NiFe pathways were obliquely-arranged on the left and right sides of the converging site, respectively. This caused a central translational force that allowed the converging and diverging of the Atto-520 biotin loaded streptavidin magnetic beads at a particular site.
我们展示了使用磁泳技术在溶液中实时在硅表面上对生物功能化超顺磁性珠进行芯片内转运。超顺磁性珠可作为生物分子载体。通过配体受体相互作用，将荧光标记的 Atto-520 生物素加载到链霉亲和素包被的磁性珠（Dynabead® M-280）上。磁路通过光刻图案化，使得半椭圆形 Ni(80)Fe(20) 元件以几百微米的长度顺序排列。外部旋转磁场用于在磁珠上施加平移力，该力与磁场强度及其梯度的乘积成正比。对于 7.9 kA m(-1) 的施加磁场，直径为 6 μm 的路径元件的弯曲边缘的平移力计算为约 1.2 pN。然而，平坦边缘的力计算为约 0.16 pN。平移力大于阻力，因此允许磁珠沿路径的弯曲边缘以定向方式移动。然而，该力不足以使磁珠沿平坦边缘移动。上侧和下侧弯曲边缘的半椭圆形 NiFe 路径分别以倾斜的方式布置在汇聚点的左右两侧。这导致了一个中央平移力，允许在特定位置汇聚和分散加载了 Atto-520 生物素的链霉亲和素磁性珠。
