Plasmonic Electricity: A Digital form of Metal-Enhanced Fluorescence

Abstract

Fluorescence technologies are entrenched in the biosciences today. In nearly all aspects of fluorescence spectroscopy light is focused and collected by a detector which converts the photon flux into a digital signal which is then displayed. To boost optical signatures many groups have shown that the close proximity of fluorescent species to fluorophores, significantly amplifies the fluorescence signatures many fold, a technology recently described as Metal-Enhanced Fluorescence by the Geddes labs1 However, hidden within these close-range near field fluorophore-metal interactions is an induced plasmonic current, directly proportional to the excitation irradiance and the concentration of the fluorophores present in the near-field, < 20 nm. The current can be read directly, opening up huge opportunities for both the amplification and the direct detection of fluorescence, i.e. digital fluorescence, such as in solar energy conversion, digital immunoassays (Figure 1), DNA detection and in fluorescence microscopy. The direct measurement of fluorescence is likely to find profound applications and implications in the biosciences and promises to change both the way we think and use fluorescence spectroscopy today.Figure 1Metal-Enhanced Fluorescence-based digital immunoassays. A model IgG-Anti-IgG assay, demonstrating the direct detection of Fluorescence.View Large Image | View Hi-Res Image | Download PowerPoint Slide1. Metal-Enhanced Fluorescence, edited by Chris D. Geddes, John Wiley and Sons, New Jersey, 2009. - In Press.