Institut Jean Lamour, Lorraine University (CNRS-UMR 7198), 54011 Nancy, France.
Sensors (Basel). 2019 Jun 26;19(13):2839. doi: 10.3390/s19132839.
The limit of detection of a biological sensor is an important parameter because, when it is optimized, it allows the detection of a reduced number of biological cells and the reduction of the detection time. This parameter can be improved upon with a reduction in electrode size, but the rate of detection is similarly reduced as well. To avoid this problem, we propose a sensor matrix composed of 20 × 20 µm² coplanar square electrodes with a standard clean room manufacturing process. However, it was observed that the exposition of electrode connection tracks to the solution reduces the normalized impedance variation. In this pursuit, we propose in this paper an analysis of electrode connection tracks on the normalized impedance variation and cutoff frequencies to biological cell measurements by impedance spectroscopy. The experimental results were obtained using the E4990A Keysight impedance analyser (Keysight Technologies, Santa Rosa, CA, USA) with a frequency band ranging from 100 Hz to 12 MHz, thus allowing for good measurement accuracy. Therefore, it was found that, for the measurements between the electrodes with 9 µm of connection tracks in contact with the solution, the normalized impedance variation was from 3.7% to 4.2% for different measurements, while, for the electrodes with 40 µm of connection tracks in contact with the solution, the normalized impedance variation was from 1.8% to 2.1% for different measurements.
生物传感器的检测极限是一个重要的参数，因为当它被优化时，可以检测到更少数量的生物细胞，并减少检测时间。通过减小电极尺寸可以改善这个参数，但检测速度也会相应降低。为了避免这个问题，我们提出了一种由 20×20µm²共面正方形电极组成的传感器矩阵，并采用标准的洁净室制造工艺。然而，我们观察到电极连接轨道暴露在溶液中会降低归一化阻抗变化。在这方面，我们在本文中提出了一种分析方法，通过阻抗谱对生物细胞测量中的电极连接轨道对归一化阻抗变化和截止频率的影响进行分析。实验结果是使用 E4990A Keysight 阻抗分析仪（Keysight Technologies，Santa Rosa，CA，USA）获得的，频率范围从 100 Hz 到 12 MHz，因此可以保证良好的测量精度。因此，我们发现，对于接触溶液的 9 µm 连接轨道电极之间的测量，不同测量的归一化阻抗变化在 3.7%到 4.2%之间，而对于接触溶液的 40 µm 连接轨道电极之间的测量，不同测量的归一化阻抗变化在 1.8%到 2.1%之间。
