Fluorescence correlation spectroscopy near individual gold nanoparticle

Dynamic behavior of fluorescent molecules near an individual gold nanoparticle is investigated experimentally by fluorescence correlation spectroscopy method. The gold particle that acts as an optical nano-antenna presents significant near-field volume reduction. The single molecule diffusion behavior is clearly observed within a reduced near-field volume due to a highly localized field enhancement. The near-field volume and fluorescence enhancement are polarization and concentration dependent and strongly depend on the properties of the gold nanoparticle. A simple approximated model is developed to fit the FCS autocorrelation curves. In principle, the single molecule analysis within the near-field volume of nanostructures could be applied to the analysis of biological membranes and intracellular processes. (C) 2011 Elsevier B.V. All rights reserved.