Particle timing and spacing control in microchannel flow by applying periodic force over space and time
Particle timing and spacing control in microchannel flow by applying periodic force over space and time
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DOI：
10.1007/s10404-020-02416-5
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发表时间：
2021-01
影响因子：
2.8
通讯作者：
K. Tatsumi;A. Noma;R. Honma;R. Kuriyama;K. Nakabe
中科院分区：
文献类型：
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作者：
K. Tatsumi;A. Noma;R. Honma;R. Kuriyama;K. Nakabe
这项研究开发了一种技术，通过在空间和时间上周期性地对颗粒施加力来控制微通道流中颗粒的时间、间距（间隔）和速度。周期力是通过通道壁上的棚车形电极通过介电泳力产生的。我们可以通过配置所施加电压的开关周期来定义粒子的时间、间隔和速度。控制颗粒穿过通道中某个位置时的间距和时间以及横截面位置的聚焦效应可以提高微流体的性能和吞吐量，特别是对于颗粒和细胞的传感、主动分选以及封装。首先通过基于微扰理论的一维分析对所提出的技术进行了评估。我们进行了数值模拟来求解介电泳力分布和粒子的运动方程，以了解棚车电极区域中力与粒子运动之间的关系。我们测量了微通道中流过棚车电极区域的微粒的速度和位置，并证明了所提出的对准和定时控制技术的性能和准确性。粒子之间的周期、粒子速度和时间的概率密度函数 (PDF) 集中在变化最小的目标值处。此外，对直径为 8、10 和 12 μm 的颗粒进行测量得出了相同的 PDF，这表明了颗粒直径合理变化的适用性。
This study develops a technique to control the timing, spacing (interval), and velocity of particles in a microchannel flow by periodically exerting forces on the particles over space and time. The periodic force was produced by dielectrophoretic force using boxcar-shaped electrodes on the channel wall. We could define the timing, interval, and velocity of the particles by configuring the on–off cycles of the applied voltage. Controlling the particle spacing and timing when it crosses a position in the channel and the focusing effect in the cross-sectional position could improve the performance and throughput of microfluidics, particularly for sensing, active sorting, and encapsulation of particles and cells. The proposed technique was first evaluated by a one-dimensional analysis based on a perturbation theory. We conducted a numerical simulation to solve the dielectrophoretic force distribution and the equation of motion of the particles to understand the relationship between the force and the particle motion in the boxcar-electrode region. We measured the velocity and position of the micro-particles flowing over the boxcar-electrode region in the microchannel and demonstrated the performance and accuracy of the proposed technique for alignment and timing control. The probability density functions (PDFs) of the period between the particles, particle velocity, and timing, concentrated at the target value with minimal variation. Furthermore, the measurement of particles with diameters of 8, 10, and 12 μm resulted in the same PDFs, which showed the applicability to a reasonable variation of particle diameters.