A Label-Free Porous Alumina Interferometric Immunosensor
A Label-Free Porous Alumina Interferometric Immunosensor
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DOI：
10.1021/nn900825q
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发表时间：
2009-10-01
期刊：
影响因子：
17.1
通讯作者：
Sailor, Michael J.
中科院分区：
文献类型：
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作者：
Alvarez, Sara D.;Li, Chang-Peng;Sailor, Michael J.
铝阳极氧化用于制备光学光滑的多孔氧化铝（Al2O3）薄膜，其孔直径约为60 nm，深约为6 μ m。捕获蛋白A通过非共价静电相互作用吸附在孔壁上，薄膜干涉光谱用于检测免疫球蛋白（IgG）的结合。多孔氧化铝膜在pH为7的水介质中具有抗腐蚀和抗溶解的稳定性，可以定量监测稳态和时间分辨的生物分子结合。裸露的多孔Al2O3表面对蛋白a的亲和力明显高于对IgG的亲和力。证实了已知的A蛋白与IgG结合的物种特异性；蛋白a修饰的传感器对兔IgG （IgG/IgY）有应答，对鸡IgG/IgY无应答。本文演示了一种“级联”或多探针传感方法，其中将特定靶标羊IgG施用于用蛋白A/兔抗羊IgG组装修饰的样品中。结合测量是用荧光素标记的IgG荧光显微镜确认的。
Anodization of Al is used to produce optically smooth porous alumina (Al2O3) films with pores similar to 60 nm in diameter and similar to 6 mu m deep. The capture protein, protein A, is adsorbed to the pore walls by noncovalent, electrostatic interactions, and thin film interference spectroscopy is used to detect binding of immunoglobulin (IgG). The porous alumina films are stable against corrosion and dissolution in aqueous media at pH 7, allowing quantitative monitoring of steady-state and time-resolved biomolecular binding. The bare porous Al2O3 surface displays a significantly greater affinity for protein A than for IgG. The known species specificity of protein A binding to IgG is confirmed; the protein-A-modified sensor responds to IgG derived from rabbit, but not chicken (IgG/IgY). A "cascaded", or multiprobe sensing approach, is demonstrated, in which a specific target, sheep IgG, is administered to a sample modified with a protein A/rabbit anti-sheep IgG assembly. Binding measurements are confirmed by fluorescence microscopy using fluorescein-labeled IgG.