title: Fluorescence enhancement at docking sites of DNA-directed self-assembled nanoantennas.
abstract: We introduce self-assembled nanoantennas to enhance the fluorescence intensity in a plasmonic hotspot of zeptoliter volume. The nanoantennas are prepared by attaching one or two gold nanoparticles (NPs) to DNA origami structures, which also incorporated docking sites for a single fluorescent dye next to one NP or in the gap between two NPs. We measured the dependence of the fluorescence enhancement on NP size and number and compare it to numerical simulations. A maximum of 117-fold fluorescence enhancement was obtained for a dye molecule positioned in the 23-nanometer gap between 100-nanometer gold NPs. Direct visualization of the binding and unbinding of short DNA strands, as well as the conformational dynamics of a DNA Holliday junction in the hotspot of the nanoantenna, show the compatibility with single-molecule assays.
authors.affiliation: NanoBioSciences Group, Institute for Physical and Theoretical Chemistry, Technische Universität Braunschweig, Hans-Sommer-Strasse 10, 38106 Braunschweig, Germany. g.acuna@tu-bs.de
authors.forename: G P
authors.initials: GP
authors.lastname: Acuna
authors.forename: F M
authors.initials: FM
authors.lastname: Möller
authors.forename: P
authors.initials: P
authors.lastname: Holzmeister
authors.forename: S
authors.initials: S
authors.lastname: Beater
authors.forename: B
authors.initials: B
authors.lastname: Lalkens
authors.forename: P
authors.initials: P
authors.lastname: Tinnefeld
mesh_terms: D004247:DNA / Q000737:chemistry* / Q000235:genetics; D045566:DNA, Cruciform; D019281:Dimerization; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D007089:Image Enhancement / Q000379:methods*; D053768:Metal Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D013050:Spectrometry, Fluorescence / Q000379:methods*
chemical_list: D045566:DNA, Cruciform; D005456:Fluorescent Dyes; D006046:Gold; D004247:DNA