Fluorescence Resonance Energy Transfer within Diblock Copolymer Micelles in the Proximity of Metal Nanoparticles

Abstract

Recently, it has been reported that localized surface plasmon resonance of metal nanoparticles (NPs) can engineer fluorescence resonance energy transfer (FRET) process. By placing metal NPs in the vicinity of donor-acceptor pairs of fluorophores, the FRET efficiency and Forster radius have been strongly modified to alter the fluorescence properties of both donors and acceptors. Since FRET is an important process in biology and optoelectronics, the metal-coupled FRET could find interesting opportunities in a number of applications. Toward this opportunity, however, it is still necessary to develop an assembling method to organize metal NPs and donor-acceptor pair of fluorophores on a nanometer scale. In this study, we investigated a simple approach based on diblock copolymer micelles to place donor-acceptor pair of fluorescent dyes around Ag NPs on solid substrate. By analyzing the fluorescence spectra, we found that the fluorescence intensities of both donors and acceptors were enhanced, but FRET efficiency was reduced by plamonic effect. The reduced FRET under metal NPs has been further discussed via the competitive decay processes of excited donors in terms of FRET and non-FRET pathways.