Microfluidic electromanipulation with capacitive detection for the mechanical analysis of cells
Microfluidic electromanipulation with capacitive detection for the mechanical analysis of cells
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DOI：
10.1063/1.2992127
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发表时间：
2008-10-01
期刊：
影响因子：
3.2
通讯作者：
Freeman, M. R.
中科院分区：
文献类型：
--
作者：
Ferrier, G. A.;Hladio, A. N.;Freeman, M. R.
细胞的机械行为可以深入了解其特性的许多方面。我们提出了一种细胞机械分析方法，该方法结合使用电操纵刺激和电容传感。为了证明这种方法，通过通道中间隔 25 μm 的一对垂直金薄膜电极检测在 25 μmx100 μm 微流体通道中流动的聚苯乙烯球和酵母细胞。通过金电极之间的电容变化来检测细胞的存在。电容传感器是耦合到电极的谐振同轴射频腔（2.3 GHz）。酵母细胞（酿酒酵母）和聚苯乙烯球的存在分别导致约 10 和 100 阿法拉 (aF) 的电容变化，在 30 Hz 带宽下实现的电容分辨率小于 2 aF。分辨率比之前文献报道的要好，并且电容变化与有限元模拟估计的值一致。通过在电极之间施加 1 MHz 的 3 V 信号，利用介电泳力捕获酵母细胞。捕获后，使用调幅和调频电压使细胞移位，以产生调制的介电泳力。使用电容和视频显微镜观察这些细胞的重复位移和松弛。
The mechanical behavior of cells offers insight into many aspects of their properties. We propose an approach to the mechanical analysis of cells that uses a combination of electromanipulation for stimulus and capacitance for sensing. To demonstrate this approach, polystyrene spheres and yeast cells flowing in a 25 mu mx100 mu m microfluidic channel were detected by a perpendicular pair of gold thin film electrodes in the channel, spaced 25 mu m apart. The presence of cells was detected by capacitance changes between the gold electrodes. The capacitance sensor was a resonant coaxial radio frequency cavity (2.3 GHz) coupled to the electrodes. The presence of yeast cells (Saccharomyces cerevisiae) and polystyrene spheres resulted in capacitance changes of approximately 10 and 100 attoFarad (aF), respectively, with an achieved capacitance resolution of less than 2 aF in a 30 Hz bandwidth. The resolution is better than previously reported in the literature, and the capacitance changes are in agreement with values estimated by finite element simulations. Yeast cells were trapped using dielectrophoretic forces by applying a 3 V signal at 1 MHz between the electrodes. After trapping, the cells were displaced using amplitude and frequency modulated voltages to produce modulated dielectrophoretic forces. Repetitive displacement and relaxation of these cells was observed using both capacitance and video microscopy.