title: FRET enhancement close to gold nanoparticles positioned in DNA origami constructs.
abstract: Here we investigate the energy transfer rates of a Förster resonance energy transfer (FRET) pair positioned in close proximity to a 5 nm gold nanoparticle (AuNP) on a DNA origami construct. We study the distance dependence of the FRET rate by varying the location of the donor molecule, D, relative to the AuNP while maintaining a fixed location of the acceptor molecule, A. The presence of the AuNP induces an alteration in the spontaneous emission of the donor (including radiative and non-radiative rates) which is strongly dependent on the distance between the donor and AuNP surface. Simultaneously, the energy transfer rates are enhanced at shorter D-A (and D-AuNP) distances. Overall, in addition to the direct influence of the acceptor and AuNP on the donor decay there is also a significant increase in decay rate not explained by the sum of the two interactions. This leads to enhanced energy transfer between donor and acceptor in the presence of a 5 nm AuNP. We also demonstrate that the transfer rate in the three "particle" geometry (D + A + AuNP) depends approximately linearly on the transfer rate in the donor-AuNP system, suggesting the possibility to control FRET process with electric field induced by 5 nm AuNPs close to the donor fluorophore. It is concluded that DNA origami is a very versatile platform for studying interactions between molecules and plasmonic nanoparticles in general and FRET enhancement in particular.
authors.affiliation: Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden. balb@chalmers.se.
authors.forename: Nesrine
authors.initials: N
authors.lastname: Aissaoui
authors.affiliation: Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden. balb@chalmers.se.
authors.forename: Kasper
authors.identifier: http://orcid.org/0000-0003-4018-4927
authors.initials: K
authors.lastname: Moth-Poulsen
authors.affiliation: Department of Applied Physics, Chalmers University of Technology, Gothenburg, Sweden.
authors.forename: Mikael
authors.initials: M
authors.lastname: Käll
authors.affiliation: School of Science and Technology, Örebro University, Örebro, Sweden.
authors.forename: Peter
authors.initials: P
authors.lastname: Johansson
authors.affiliation: Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden. balb@chalmers.se.
authors.forename: L Marcus
authors.initials: LM
authors.lastname: Wilhelmsson
authors.affiliation: Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden. balb@chalmers.se.
authors.forename: Bo
authors.identifier: http://orcid.org/0000-0002-5991-7863
authors.initials: B
authors.lastname: Albinsson
mesh_terms: D004247:DNA / Q000737:chemistry*; D031541:Fluorescence Resonance Energy Transfer; D005456:Fluorescent Dyes; D006046:Gold; D053768:Metal Nanoparticles
chemical_list: D005456:Fluorescent Dyes; D006046:Gold; D004247:DNA