Nguyen T A, Echtermeyer D, Barthel A, Urban G, Pliquett U
Department of Physics, Le Quy Don Technical University, Ha Noi, Viet Nam.
Institut für Bioprozess- und Analysenmeßtechnik, Heilbad Heiligenstadt, Germany.
J Electr Bioimpedance. 2020 Jul 24;11(1):49-56. doi: 10.2478/joeb-2020-0008. eCollection 2020 Jan.
Designing proper frontend electronics is critical in the development of highly sophisticated electrode systems. Multielectrode arrays for measuring electrical signals or impedance require multichannel readout systems. Even more challenging is the differential or ratiometric configuration with simultaneous assessment of measurement and reference channels. In this work, an eight-channel frontend was developed for contacting a 2×8 electrode array (8 measurement and 8 reference electrodes) with a large common electrode to the impedance gain-phase analyzer Solartron 1260 (S-1260). Using the three independent and truly parallel monitor channels of the S-1260, impedance of trapped cells and reference material was measured at the same time, thereby considerably increasing the performance of the device. The frontend electronics buffers the generator output and applies a potentiostatic signal to the common electrode of the chip. The applied voltage is monitored using the current monitor of the S-1260 via voltage/current conversion. The frontend monitors the current through the electrodes and converts it to a voltage fed into the voltage monitors of the S-1260. For assessment of the 8 electrode pairs featured by the chip, a relay-based multiplexer was implemented. Extensive characterization and calibration of the frontend were carried out in a frequency range between 100 Hz and 1 MHz. Investigating the influence of the multiplexer and the frontend electronics, direct measurement with and without frontend was compared. Although differences were evident, they have been negligible below one per cent. The significance of measurement using the complex S-1260-frontend-electrode was tested using Kohlrausch's law. The impedance of an electrolytic dilution series was measured and compared to the theoretical values. The coincidence of measured values and theoretical prediction serves as an indicator for electrode sensitivity to cell behavior. Monitoring of cell behavior on the microelectrode surface will be shown as an example.
设计合适的前端电子设备对于高度复杂的电极系统的开发至关重要。用于测量电信号或阻抗的多电极阵列需要多通道读出系统。更具挑战性的是同时评估测量通道和参考通道的差分或比例配置。在这项工作中，开发了一种八通道前端，用于将一个2×8电极阵列（8个测量电极和8个参考电极）与一个大的公共电极连接到阻抗增益相位分析仪Solartron 1260（S - 1260）。利用S - 1260的三个独立且真正并行的监测通道，同时测量捕获细胞和参考材料的阻抗，从而显著提高了该设备的性能。前端电子设备缓冲发生器输出，并向芯片的公共电极施加恒电位信号。通过电压/电流转换，利用S - 1260的电流监测器监测施加的电压。前端监测通过电极的电流，并将其转换为馈入S - 1260电压监测器的电压。为了评估芯片的8对电极，实现了一个基于继电器的多路复用器。在100 Hz至1 MHz的频率范围内对前端进行了广泛的特性表征和校准。研究了多路复用器和前端电子设备的影响，比较了有无前端时的直接测量。尽管差异明显，但在百分之一以下可忽略不计。使用科尔劳施定律测试了使用复杂的S - 1260 - 前端 - 电极进行测量的意义。测量了电解稀释系列的阻抗，并与理论值进行了比较。测量值与理论预测的吻合度作为电极对细胞行为敏感性的指标。将以微电极表面细胞行为的监测为例进行展示。
