Bruch Richard, Kling André, Urban Gerald A, Dincer Can
Department of Microsystems Engineering, University of Freiburg.
Department of Microsystems Engineering, University of Freiburg; Department of Biosystems Science and Engineering, ETH Zurich.
J Vis Exp. 2017 Sep 19(127):56105. doi: 10.3791/56105.
In recent years, biomarker diagnostics became an indispensable tool for the diagnosis of human disease, especially for the point-of-care diagnostics. An easy-to-use and low-cost sensor platform is highly desired to measure various types of analytes (e.g., biomarkers, hormones, and drugs) quantitatively and specifically. For this reason, dry film photoresist technology - enabling cheap, facile, and high-throughput fabrication - was used to manufacture the microfluidic biosensor presented here. Depending on the bioassay used afterwards, the versatile platform is capable of detecting various types of biomolecules. For the fabrication of the device, platinum electrodes are structured on a flexible polyimide (PI) foil in the only clean-room process step. The PI foil serves as a substrate for the electrodes, which are insulated with an epoxy-based photoresist. The microfluidic channel is subsequently generated by the development and lamination of dry film photoresist (DFR) foils onto the PI wafer. By using a hydrophobic stopping barrier in the channel, the channel is separated into two specific areas: an immobilization section for the enzyme-linked assay and an electrochemical measurement cell for the amperometric signal readout. The on-chip bioassay immobilization is performed by the adsorption of the biomolecules to the channel surface. The glucose oxidase enzyme is used as a transducer for electrochemical signal generation. In the presence of the substrate, glucose, hydrogen peroxide is produced, which is detected at the platinum working electrode. The stop-flow technique is applied to obtain signal amplification along with rapid detection. Different biomolecules can quantitatively be measured by means of the introduced microfluidic system, giving an indication of different types of diseases, or, in regard to therapeutic drug monitoring, facilitating a personalized therapy.
近年来，生物标志物诊断已成为人类疾病诊断不可或缺的工具，尤其是即时诊断。人们迫切需要一种易于使用且低成本的传感器平台，用于定量和特异性地测量各种类型的分析物（如生物标志物、激素和药物）。因此，采用了能够实现廉价、简便且高通量制造的干膜光刻胶技术来制造本文介绍的微流控生物传感器。根据后续使用的生物测定方法，该通用平台能够检测各种类型的生物分子。在制造该设备时，在唯一的洁净室工艺步骤中，在柔性聚酰亚胺（PI）箔上构建铂电极。PI箔用作电极的基板，电极用环氧基光刻胶绝缘。随后，通过将干膜光刻胶（DFR）箔显影并层压到PI晶圆上来生成微流控通道。通过在通道中使用疏水阻挡层，通道被分隔成两个特定区域：用于酶联测定的固定化部分和用于安培信号读出的电化学测量池。芯片上的生物测定固定化通过生物分子吸附到通道表面来实现。葡萄糖氧化酶用作产生电化学信号的换能器。在底物葡萄糖存在的情况下，会产生过氧化氢，在铂工作电极上进行检测。应用停流技术以实现信号放大并快速检测。借助引入的微流控系统可以定量测量不同的生物分子，从而指示不同类型的疾病，或者在治疗药物监测方面，有助于实现个性化治疗。
