Integrating microfluidics with biosensors is of great research interest with the increasing trend of lab-on-the chip and point-of-care devices. Though there have been numerous studies performed relating microfluidics to the biosensing mechanisms, the study of the sensitivity variation due to microfluidic flow is very much limited. In this paper, the sensitivity of interdigitated electrodes was evaluated at the static drop condition and the microfluidic flow condition. In addition, this study demonstrates the use of gold nanoparticles to enhance the sensor signal response and provides experimental results of the capacitance difference during cancer antigen-125 (CA-125) antigen–antibody conjugation at multiple concentrations of CA-125 antigens. The experimental results also provide evidence of disease-specific detection of CA-125 antigen at multiple concentrations with the increase in capacitive signal response proportional to the concentration of the CA-125 antigens. The capacitive signal response of antigen–antibody conjugation on interdigitate electrodes has been enhanced by approximately 2.8 times (from 260.80 to 736.33 pF at 20 kHz frequency) in static drop condition and approximately 2.5 times (from 205.85 to 518.48 pF at 20 kHz frequency) in microfluidic flow condition with gold nanoparticle-coating. The capacitive signal response is observed to decrease at microfluidic flow condition at both plain interdigitated electrodes (from 260.80 to 205.85 pF at 20 kHz frequency) and gold nano particle coated interdigitated electrodes (from 736.33 to 518.48 pF at 20 kHz frequency), due to the strong shear effect compared to static drop condition. However, the microfluidic channel in the biosensor has the potential to increase the signal to noise ratio due to plasma separation from the whole blood and lead to the increase concentration of the biomarkers in the blood volume for sensing.

中文翻译：

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在基于叉指电极的微流生物传感器上使用金纳米颗粒检测癌症抗原（CA-125）。

随着芯片实验室和即时医疗设备的发展趋势，将微流控技术与生物传感器集成在一起具有极大的研究兴趣。尽管已经进行了许多有关微流体与生物传感机制的研究，但是由于微流体流动引起的灵敏度变化的研究非常有限。本文在静电跌落条件和微流体流动条件下评估了叉指电极的灵敏度。此外，这项研究证明了使用金纳米颗粒增强传感器信号响应，并提供了在多种浓度的CA-125抗原下癌症抗原125（CA-125）抗原-抗体结合过程中电容差异的实验结果。实验结果还提供了多种浓度的CA-125抗原的疾病特异性检测的证据，电容信号响应的增加与CA-125抗原的浓度成正比。在静态跌落条件下，指间电极上抗原-抗体结合的电容信号响应已提高了约2.8倍（在20 kHz频率下从260.80至736.33 pF）和在静态下降条件下约2.5倍（从20.205频率从205.85至518.48 pF）增强了。金纳米颗粒涂层的微流体流动条件。在微流体流动条件下，在普通的交叉指状电极（频率为20 kHz时从260.80至205.85 pF）和涂有金纳米颗粒的交叉指状电极（频率为20 kHz时从736.33至518.48 pF）时，电容信号响应均下降。与静态跌落条件相比，具有较强的剪切作用。然而，由于从全血中分离血浆，生物传感器中的微流体通道具有增加信噪比的潜力，并导致用于检测的血液中生物标志物的浓度增加。