Biological sensing and interface design in gold island film based localized plasmon transducers
| Autor: | Israel Rubinstein, Tatyana Bendikov, Alexander Vaskevich, Aharon Rabinkov, Tanya Karakouz |
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| Rok vydání: | 2008 |
| Předmět: |
Transductor
Chemistry business.industry Surface plasmon Proteins Biosensing Techniques Surface Plasmon Resonance Microscopy Atomic Force Evaporation (deposition) Chorionic Gonadotropin Analytical Chemistry Nanostructures Antigen-Antibody Reactions Transducer Optics Ellipsometry Antibody Specificity Immunoglobulin G Spectrophotometry Ultraviolet Gold Surface plasmon resonance business Refractive index Plasmon |
| Zdroj: | Analytical chemistry. 80(19) |
| ISSN: | 1520-6882 |
| Popis: | Discontinuous, island-type gold films (typicallyor = 10 nm nominal thickness) prepared by evaporation of the metal on transparent substrates show a localized surface plasmon resonance (LSPR) extinction in the visible-to-NIR range and can be used as optical transducers for monitoring local refractive index change. Such transducers, operated in the transmission configuration, provide an effective scheme for label-free biological sensing using basic spectrophotometric equipment. Optimization of the sensitivity of LPSR transducers requires consideration of the distance between the metal island surface and the bound analyte, strongly affecting the optical response due to the fast decay of the evanescent field of localized plasmons. In the present work Au island based LSPR transducers were used to monitor antibody-antigen interactions, demonstrating the effect of the biorecognition interface thickness. Evaporated Au island films derivatized with IgG or hCG antigens were used as biological recognition elements for selective sensing of antibody binding, distinguishing between specific and nonspecific interactions. The LSPR results are supported by XPS and ellipsometry data as well as by AFM and HRSEM imaging, the latter providing actual visualization of the two protein binding steps. Increase of the recognition interface thickness leads to a concomitant decrease in the extinction and wavelength sensitivity, generally conforming to a model of an exponentially decaying surface plasmon (SP) evanescent field. |
| Databáze: | OpenAIRE |
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