Yeom Se-Hyuk, Kim Ok-Geun, Kang Byoung-Ho, Kim Kyu-Jin, Yuan Heng, Kwon Dae-Hyuk, Kim Hak-Rin, Kang Shin-Won
School of Electrical Engineering and Computer Science, Kyungpook National University, 1370 Sankyuk-dong, Bukgu, 702-701 Daegu, South Korea.
Opt Express. 2011 Nov 7;19(23):22882-91. doi: 10.1364/OE.19.022882.
We propose a design for a highly sensitive biosensor based on nanostructured anodized aluminum oxide (AAO) substrates. A gold-deposited AAO substrate exhibits both optical interference and localized surface plasmon resonance (LSPR). In our sensor, application of these disparate optical properties overcomes problems of limited sensitivity, selectivity, and dynamic range seen in similar biosensors. We fabricated uniform periodic nanopore lattice AAO templates by two-step anodizing and assessed their suitability for application in biosensors by characterizing the change in optical response on addition of biomolecules to the AAO template. To determine the suitability of such structures for biosensing applications, we immobilized a layer of C-reactive protein (CRP) antibody on a gold coating atop an AAO template. We then applied a CRP antigen (Ag) atop the immobilized antibody (Ab) layer. The shift in reflectance is interpreted as being caused by the change in refractive index with membrane thickness. Our results confirm that our proposed AAO-based biosensor is highly selective toward detection of CRP antigen, and can measure a change in CRP antigen concentration of 1 fg/ml. This method can provide a simple, fast, and sensitive analysis for protein detection in real-time.
我们提出了一种基于纳米结构化阳极氧化铝（AAO）基底的高灵敏度生物传感器设计。沉积有金的AAO基底展现出光学干涉和局域表面等离子体共振（LSPR）。在我们的传感器中，利用这些不同的光学特性克服了类似生物传感器中灵敏度、选择性和动态范围有限的问题。我们通过两步阳极氧化制备了均匀的周期性纳米孔晶格AAO模板，并通过表征向AAO模板中添加生物分子时光学响应的变化来评估其在生物传感器中的适用性。为了确定这种结构在生物传感应用中的适用性，我们在AAO模板顶部的金涂层上固定了一层C反应蛋白（CRP）抗体。然后我们在固定的抗体（Ab）层顶部施加CRP抗原（Ag）。反射率的变化被解释为由膜厚度引起的折射率变化所致。我们的结果证实，我们提出的基于AAO的生物传感器对CRP抗原的检测具有高度选择性，并且能够检测到浓度为1 fg/ml的CRP抗原变化。该方法可为蛋白质检测提供一种简单、快速且灵敏的实时分析方法。
