We present design and experimental implementation of electrostatic comb-drive actuators in solutions of high conductivity relevant for biological cells. The actuators are operated in the frequency range 1-10 MHz in ionic and biological cell culture media, with ionic strengths up to 150 mmol/L. Typical displacement is 3.5 mum at an applied peak-to-peak signal of 5 V. Two different actuation schemes are presented and tested for performance at high frequency. A differential drive design is demonstrated to overcome the attenuation due to losses in parasitic impedances. The frequency dependence of the electrostatic force has been characterized in media of different ionic strengths. Circuit models for the electric double layer phenomena are used to understand and predict the actuator behavior. The actuator is integrated into a planar force sensing system to measure the stiffness of cells cultured on suspended structures.

中文翻译：

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导电生物介质中的 MEMS 静电驱动

我们介绍了在与生物细胞相关的高电导率解决方案中静电梳状驱动执行器的设计和实验实施。执行器在离子和生物细胞培养基中的频率范围为 1-10 MHz，离子强度高达 150 mmol/L。在应用 5 V 的峰峰值信号时，典型位移为 3.5 μm。提出了两种不同的驱动方案，并测试了其在高频下的性能。演示了一种差分驱动设计，以克服由于寄生阻抗损失引起的衰减。静电力的频率依赖性已在不同离子强度的介质中表征。双电层现象的电路模型用于理解和预测致动器行为。