Electrically polarizable micro‐ and nanoparticles and droplets can be trapped using the gradient electric field of electrodes. But the spatial profile of the resultant dielectrophoretic force is fixed once the electrode structure is defined. To change the force profile, entire complex lab‐on‐a‐chip systems must be re‐fabricated with modified electrode structures. To overcome this problem, we propose an approach for the dynamic control of the spatial profile of the dielectrophoretic force by interfacing the trap electrodes with a resistor and an inductor to form a resonant resistor–inductor–capacitor (RLC) circuit. Using a dielectrophoretically trapped water droplet suspended in silicone oil, we show that the resonator amplitude, detuning, and linewidth can be continuously varied by changing the supply voltage, supply frequency, and the circuit resistance to obtain the desired trap depth, range, and stiffness. We show that by proper tuning of the resonator, the trap range can be extended without increasing the supply voltage, thus preventing sensitive samples from exposure to high electric fields at the stable trapping position. Such unprecedented dynamic control of dielectrophoretic forces opens avenues for the tunable active manipulation of sensitive biological and biochemical specimen in droplet microfluidic devices used for single‐cell and biochemical reaction analysis.

中文翻译：

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使用共振调谐动态控制介电泳

可以使用电极的梯度电场捕获可电极化的微米颗粒、纳米颗粒和液滴。但是，一旦定义了电极结构，所产生的介电泳力的空间分布就固定了。为了改变力分布，必须使用修改后的电极结构重新制造整个复杂的芯片实验室系统。为了克服这个问题，我们提出了一种动态控制介电泳力空间分布的方法，通过将陷阱电极与电阻器和电感器连接以形成谐振电阻-电感器-电容器（RLC）电路。使用悬浮在硅油中的介电泳捕获水滴，我们表明可以通过改变电源电压、电源频率和电路电阻来连续改变谐振器振幅、失谐和线宽，以获得所需的捕获深度、范围和刚度。我们表明，通过适当调整谐振器，可以在不增加电源电压的情况下扩展捕获范围，从而防止敏感样品在稳定捕获位置暴露于高电场。这种前所未有的介电泳力动态控制为用于单细胞和生化反应分析的液滴微流体装置中敏感生物和生化样本的可调主动操作开辟了途径。