Letter abstract
Nature Materials 8, 867 - 871 (2009)
Published online: 11 October 2009 | doi:10.1038/nmat2546
Subject Categories: Optical, photonic and optoelectronic materials | Sensors and biosensors
Plasmonic nanorod metamaterials for biosensing
A. V. Kabashin1,2, P. Evans3, S. Pastkovsky2, W. Hendren3, G. A. Wurtz3,5, R. Atkinson3, R. Pollard3, V. A. Podolskiy4 & A. V. Zayats3
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 events1, 2, 3, 4. Despite undisputed advantages, including spectral tunability3, strong enhancement of the local electric field5, 6 and much better adaptability to modern nanobiotechnology architectures7, localized plasmons demonstrate orders of magnitude lower sensitivity compared with their guided counterparts3. 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 30,000 nm 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.
- Laboratoire Lasers, Plasmas et Procédés Photoniques (LP3 UMR 6182 CNRS), Faculté des Sciences de Luminy, Université de Méditerranée, 163 Avenue de Luminy, 13288 Marseille Cedex 09, France
- Department of Engineering Physics, École Polytechnique de Montréal, Québec H3C 3A7, Canada
- Centre for Nanostructured Media, The Queen's University of Belfast, Belfast BT7 1NN, UK
- Physics Department, Oregon State University, 301 Weniger Hall, Corvallis, Oregon 97331, USA
- Present address: Department of Chemistry and Physics, University of North Florida, Jacksonville, Florida 32224, USA
Correspondence to: A. V. Zayats3 e-mail: a.zayats@qub.ac.uk
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