Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu 300, Taiwan.
Lab Chip. 2013 Aug 7;13(15):3098-104. doi: 10.1039/c3lc50457c.
A magnetic zigzag nanowire device was designed for single cell biosensing. Nanowires with widths of 150, 300, 500, and 800 nm were fabricated on silicon trenches by electron beam lithography, electron beam evaporation, and lift-off processes. Magnetoresistance measurements were performed before and after the attachment of a single magnetic cell to the nanowires to characterize the magnetic signal change due to the influence of the magnetic cell. Magnetoresistance responses were measured in different magnetic field directions, and the results showed that this nanowire device can be used for multi-directional detection. It was observed that the highest switching field variation occurred in a 150 nm wide nanowire when the field was perpendicular to the substrate plane. On the other hand, the highest magnetoresistance ratio variation occurred in a 800 nm wide nanowire also when the field was perpendicular to the substrate plane. Besides, the trench-structured substrate proposed in this study can fix the magnetic cell to the sensor in a fluid environment, and the stray field generated by the corners of the magnetic zigzag nanowires has the function of actively attracting the magnetic cells for detection.
设计了一种用于单细胞生物传感的磁性锯齿形纳米线器件。通过电子束光刻、电子束蒸发和剥离工艺，在硅沟槽上制造了宽度为 150、300、500 和 800nm 的纳米线。在将单个磁性细胞附着到纳米线之前和之后进行磁阻测量，以表征由于磁性细胞的影响而导致的磁信号变化。在不同的磁场方向下测量磁阻响应，结果表明该纳米线器件可用于多向检测。观察到当磁场垂直于基底平面时，在 150nm 宽的纳米线中发生了最高的开关场变化。另一方面，当磁场垂直于基底平面时，在 800nm 宽的纳米线中发生了最高的磁阻比变化。此外，本研究中提出的沟槽结构衬底可以将磁性细胞固定在传感器上，处于流体环境中，而磁性锯齿形纳米线的拐角产生的杂散场具有主动吸引磁性细胞进行检测的功能。
