Improving particle detection sensitivity of a microfluidic resistive pulse sensor by a novel electrokinetic flow focusing method
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- 作者：Zhijian Liu ; Jun Li ; Jiandong Yang ; Yongxin Song…
- 关键词：Resistive pulse sensor ; Electrokinetic flow focusing ; Detection sensitivity
- 刊名：Microfluidics and Nanofluidics
- 出版年：2017
- 出版时间：January 2017
- 年：2017
- 卷：21
- 期：1
- 全文大小：
- 刊物类别：Engineering
- 刊物主题：Engineering Fluid Dynamics; Biomedical Engineering; Analytical Chemistry; Nanotechnology and Microengineering;
- 出版者：Springer Berlin Heidelberg
- ISSN：1613-4990
- 卷排序：21
文摘
A novel and simple method of improving the particle detection sensitivity of a microfluidic resistive pulse sensor was presented in this paper. This novel electrokinetic flow focusing method utilizes a focusing solution (with high resistivity) flowing from the upstream focusing channel to the downstream focusing channel. The focusing solution in the sensing gate works like a virtual insulation wall that greatly narrows the gate and thus improves the detection sensitivity. An equation was derived to relate the magnitude of the output signal to the resistivity and the width of the focusing solution. The width of the focused particle solution under different voltages was numerically predicted. The results show that the magnitude of output signal increases with the decrease in the width of the focused particle stream. More importantly, the detection sensitivity can be improved by decreasing the space occupied by the focusing solution in the upstream and downstream channels as much as possible. Detection of 1 μm particle with a sensing gate of 30 × 40 × 10 μm (width × length × height) was successfully achieved. The proposed method is simple and advantageous in detecting smaller particles without fabricating a small sensing gate.