Centre for Biotechnology and Biomedicine (BBZ), University of Leipzig, Division of Molecular Biological-Biochemical Processing Technology, Deutscher Platz 5, D-04103 Leipzig, Germany.
Lab Chip. 2011 Sep 7;11(17):2884-92. doi: 10.1039/c1lc20267g. Epub 2011 Jul 13.
Electrochemical biosensors allow simple, fast and sensitive analyte detection for various analytical problems. Especially immunosensors are favourable due to specificity and affinity of antigen recognition by the associated antibody. We present a novel electrode array qualified for parallel analysis and increased sample throughput. The chip has nine independent sample chambers. Each chamber contains a circular gold working electrode with a diameter of 1.9 mm that is surrounded by a ring-shaped auxiliary electrode with a platinum surface. The corresponding silver/silver chloride reference electrodes are embedded in a sealing lid. The chip is open to the full range of electrochemical real-time detection methods. Among these techniques, impedance spectroscopy is an attractive tool to detect fast and label-free interfacial changes originating from the biorecognition event at the electrode surface. The capabilities of the novel electrode array are demonstrated using the example of tumour marker tenascin C detection. This glycoprotein of the extracellular matrix is expressed in cancerous tissues, especially in solid tumours such as glioma or breast carcinoma. Electrodes covered with specific antibodies were exposed to tenascin C containing samples. Non-occupied binding sites were identified using a secondary peroxidase-conjugated antibody that generated an insoluble precipitate on the electrode in a subsequent amplification procedure. The charge transfer resistance obtained from impedimetric analysis of ferri-/ferrocyanide conversion at the electrode served as analytic parameter. This assay detected 14 ng (48 fmol) tenascin C that is sufficient for clinical diagnostics. The electrode surface could be regenerated at least 20-fold without loss of its analytical performance.
电化学生物传感器允许对各种分析问题进行简单、快速和灵敏的分析物检测。特别是免疫传感器由于其相关抗体对抗原识别的特异性和亲和力而受到青睐。我们提出了一种新型的电极阵列，可用于并行分析和增加样品通量。该芯片有九个独立的样品腔。每个腔室包含一个直径为 1.9 毫米的圆形金工作电极，周围是一个带有铂表面的环形辅助电极。相应的银/氯化银参比电极嵌入在密封盖上。该芯片可用于全范围的电化学实时检测方法。在这些技术中，阻抗谱是一种很有吸引力的工具，可以检测源自电极表面生物识别事件的快速和无标记的界面变化。使用肿瘤标志物 tenascin C 的检测示例来证明新型电极阵列的功能。这种细胞外基质的糖蛋白在癌组织中表达，特别是在固体肿瘤中，如神经胶质瘤或乳腺癌。用特异性抗体覆盖的电极暴露于含有 tenascin C 的样品中。在后续的放大过程中，使用二次过氧化物酶结合抗体来识别非占据的结合位点，该抗体在电极上生成不溶性沉淀。通过在电极上进行 ferri-/ferrocyanide 转换的阻抗分析获得的电荷转移电阻作为分析参数。该测定法检测到 14 ng（48 fmol）tenascin C，足以用于临床诊断。电极表面可至少再生 20 倍而不会损失其分析性能。
