Plasmonic nanorod metamaterials for biosensing
Plasmonic nanorod metamaterials for biosensing
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DOI：
10.1038/nmat2546
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发表时间：
2009-11-01
期刊：
影响因子：
41.2
通讯作者：
Zayats, A. V.
中科院分区：
文献类型：
--
作者：
Kabashin, A. V.;Evans, P.;Zayats, A. V.
无标记等离子体生物传感器依靠表面等离子体激元或连续或纳米结构贵金属表面的局域表面等离子体来检测分子结合事件(1-4)。尽管具有无可争辩的优势，包括光谱可调谐(3)，局部电场(5，6)的强烈增强以及对现代纳米生物技术体系的更好的适应性(7)，但定域等离子激元的灵敏度比它们的导引等离子激元低一个数量级(3)。在这里，我们展示了一种使用等离子体超材料的生物传感技术的改进，这种材料能够在多孔性纳米棒层中支持导模。由于探测场和纳米棒之间结合的活性生物物质以及层内强烈的等离子激元介导的能量限制之间的大量重叠，这种超材料对棒之间介质的折射率变化(每个折射率单位超过30,000 nm)提供了增强的敏感性。我们使用标准的链霉亲和素-生物素亲和模型证明了我们的方法的可行性，并记录了与传统的无标记等离子体设备相比，小分析物的检测极限有了显著的提高。
Label-free plasmonic biosensors rely either on surface plasmon polaritons or on localized surface plasmons on continuous or nanostructured noble-metal surfaces to detect molecular-binding events(1-4). Despite undisputed advantages, including spectral tunability(3), strong enhancement of the local electric field(5,6) and much better adaptability to modern nanobiotechnology architectures(7), localized plasmons demonstrate orders of magnitude lower sensitivity compared with their guided counterparts(3). Here, we demonstrate an improvement in biosensing technology using a plasmonic metamaterial that is capable of supporting a guided mode in a porous nanorod layer. Benefiting from a substantial overlap between the probing field and the active biological substance incorporated between the nanorods and a strong plasmon-mediated energy confinement inside the layer, this metamaterial provides an enhanced sensitivity to refractive-index variations of the medium between the rods (more than 30,000nm per refractive-index unit). We demonstrate the feasibility of our approach using a standard streptavidin-biotin affinity model and record considerable improvement in the detection limit of small analytes compared with conventional label-free plasmonic devices.