This paper reports a study on developing of a protein detection biochip based on interdigitated array electrodes (IDAEs) capacitive immunosensor. The protein after being preconcentrated in a detection region will be selectively captured and detected by the capacitive immunosensor. Using electrical impedance spectroscopy operated at high-frequency in the range of 100 kHz–1 MHz, the capacitance of the gold electrode is determined and the antibody surface modification steps can be also monitored. The experiment results show the capacitance changes in accordance with the adding biochemical layer on gold electrodes for each step of the antibody surface modification. In particular, the total impedance operated at 1 MHz frequency has been seen to change from 2.1 kΩ of bare chip (before antibody surface modification) to 8 kΩ after antibody surface modification process while the serial capacitance is recorded to reduce steadily from 450 pF to 55 pF. Also, the efficiency of protein chip was investigated by implementing the measurement of 10 µM BSA with and without preconcentration process. The measurement results have shown the sensitivity increasing significantly after the protein is preconcentrated in this chip. The results demonstrate high efficiency of protein detection can be achieved by operating high frequency capacitive measurement on IDAEs capacitive immunosensor.

中文翻译：

---

基于高频叉指阵列电极的电容式生物传感器，用于蛋白质检测

本文报道了基于叉指阵列电极（IDAEs）电容免疫传感器的蛋白质检测生物芯片的开发研究。预浓缩在检测区域中的蛋白质将被电容式免疫传感器选择性地捕获和检测。使用在100 kHz–1 MHz范围内的高频下运行的电阻抗光谱法，可以确定金电极的电容，还可以监测抗体表面修饰步骤。实验结果表明，对于抗体表面修饰的每个步骤，电容都根据在金电极上添加生化层而变化。特别是，在1 MHz频率下工作的总阻抗已从2改变。1kΩ裸芯片（抗体表面修饰前）至抗体表面修饰过程后的8kΩ，同时记录了串联电容，以将其从450 pF稳定地减小至55 pF。此外，通过在有和无预浓缩过程中进行10 µM BSA的测量来研究蛋白质芯片的效率。测量结果表明，在该芯片中预浓缩蛋白质后，灵敏度显着提高。结果表明，可以通过在IDAE的电容式免疫传感器上进行高频电容测量来实现蛋白质检测的高效率。测量结果表明，在该芯片中预浓缩蛋白质后，灵敏度显着提高。结果表明，可以通过在IDAE的电容式免疫传感器上进行高频电容测量来实现蛋白质检测的高效率。测量结果表明，在该芯片中预浓缩蛋白质后，灵敏度显着提高。结果表明，可以通过在IDAE的电容式免疫传感器上进行高频电容测量来实现蛋白质检测的高效率。