Confining the sampling volume for Fluorescence Correlation Spectroscopy using a sub-wavelength sized aperture

For the observation of single molecule dynamics with fluorescence fluctuation spectroscopy (FFS) very low fluorophore concentrations are necessary. For in vitro measurements, this requirement is easy to fulfill. In biology however, micromolar concentrations are often encountered and may pose a real...

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Bibliographic Details
Published in:Optics express 2006-01, Vol.14 (2), p.956-969
Main Authors: Leutenegger, Marcel, Gösch, Michael, Perentes, Alexandre, Hoffmann, Patrik, Martin, Olivier J F, Lasser, Theo
Format: Article
Language:English
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Summary:For the observation of single molecule dynamics with fluorescence fluctuation spectroscopy (FFS) very low fluorophore concentrations are necessary. For in vitro measurements, this requirement is easy to fulfill. In biology however, micromolar concentrations are often encountered and may pose a real challenge to conventional FFS methods based on confocal instrumentation. We show a higher confinement of the sampling volume in the near-field of sub-wavelength sized apertures in a thin gold film. The gold apertures have been measured and characterized with fluorescence correlation spectroscopy (FCS), indicating light confinement beyond the far-field diffraction limit. We measured a reduction of the effective sampling volume by an order of magnitude compared to confocal instrumentation.
ISSN:1094-4087
1094-4087
DOI:10.1364/opex.14.000956