Maier Irene, Morgan Michael R A, Lindner Wolfgang, Pittner Fritz
Max F. Perutz Laboratories, Department of Biochemistry, University of Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria.
Anal Chem. 2008 Apr 15;80(8):2694-703. doi: 10.1021/ac702107k. Epub 2008 Mar 22.
An optical immunochip biosensor has been developed as a rapid method for allergen detection in complex food matrixes, and its application evaluated for the detection of the egg white allergens, ovalbumin and ovomucoid. The optical near-field phenomenon underlying the basic principle of the sensor design is called resonance-enhanced absorption (REA), which utilizes gold nanoparticles (Au NPs) as signal transducers in a highly sensitive interferometric setup. Using this approach, a novel, simple, and rapid colorimetric solid-phase immunoassay on a planar chip substrate was realized in direct and sandwich assay formats, with a detection system that does not require any instrumentation for readout. Semiquantitative immunochemical responses are directly visible to the naked eye of the analyst. The biosensor shows concentration-dependent color development by capturing antibody-functionalized Au NPs on allergen-coated chips and has a detection limit of 1 ng/mL. To establish a rapid method, we took advantage of the physicochemical microenvironment of the Au NP-antibody bioconjugate to be bound directly over an interacting poly(styrene-methyl methacrylate) interlayer by an immobilized antigen. In the direct assay format, a coating time with allergen of only 5 min under "soft" nondenaturing conditions was sufficient for accurate reproducibility and sensitivity. In conclusion, the REA-based immunochip sensor is easy to fabricate, is reproducible and selective in its performance, has minimal technical requirements, and will enable high-throughput screening of affinity binding interactions in technological and medical applications.
一种光学免疫芯片生物传感器已被开发出来，作为在复杂食品基质中快速检测过敏原的方法，并对其在检测蛋清过敏原卵清蛋白和卵类黏蛋白中的应用进行了评估。传感器设计基本原理背后的光学近场现象称为共振增强吸收（REA），它在高灵敏度干涉测量装置中利用金纳米颗粒（Au NPs）作为信号传感器。使用这种方法，在平面芯片基板上以直接和夹心检测形式实现了一种新颖、简单且快速的比色固相免疫测定，其检测系统无需任何读出仪器。半定量免疫化学反应对分析人员肉眼来说是直接可见的。该生物传感器通过在过敏原包被的芯片上捕获抗体功能化的金纳米颗粒显示出浓度依赖性显色，检测限为1 ng/mL。为了建立一种快速方法，我们利用了金纳米颗粒 - 抗体生物共轭物的物理化学微环境，使其通过固定化抗原直接结合在相互作用的聚（苯乙烯 - 甲基丙烯酸甲酯）中间层上。在直接检测形式中，在“温和”的非变性条件下，仅用5分钟的过敏原包被时间就足以实现准确的重现性和灵敏度。总之，基于REA的免疫芯片传感器易于制造，性能可重现且具有选择性，技术要求最低，并将能够在技术和医学应用中对亲和结合相互作用进行高通量筛选。
