Plasmonic Nanoantennas Enable Forbidden Förster Dipole-Dipole Energy Transfer and Enhance the FRET Efficiency.
Förster resonance energy transfer (FRET) plays a key role in biochemistry, organic photovoltaics, and lighting sources. FRET is commonly used as a nanoruler for the short (nanometer) distance between donor and acceptor dyes, yet FRET is equally sensitive to the mutual dipole orientation. The orientation dependence complicates the FRET analysis in biological samples and may even lead to the absence of FRET for perpendicularly oriented donor and acceptor dipoles. Here, we exploit the strongly inhomogeneous and localized fields in plasmonic nanoantennas to open new energy transfer routes, overcoming the limitations from the mutual dipole orientation to ultimately enhance the FRET efficiency. We demonstrate that the simultaneous presence of perpendicular near-field components in the nanoantenna sets favorable energy transfer routes that increase the FRET efficiency up to 50% for nearly perpendicular donor and acceptor dipoles. This new facet of plasmonic nanoantennas enables dipole-dipole energy transfer that would otherwise be forbidden in a homogeneous environment. As such, our approach further increases the applicability of single-molecule FRET over diffraction-limited approaches, with the additional benefits of higher sensitivities and higher concentration ranges toward physiological levels.
CNRS, Aix Marseille Université, Centrale Marseille, Institut Fresnel, UMR 7249, 13013Marseille, France.
Juan
J
de Torres
ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology , 08860 Barcelona, Spain.
Mathieu
M
Mivelle
CNRS, Aix Marseille Université, Centrale Marseille, Institut Fresnel, UMR 7249, 13013Marseille, France.
Satish Babu
SB
Moparthi
CNRS, Aix Marseille Université, Centrale Marseille, Institut Fresnel, UMR 7249, 13013Marseille, France.
Hervé
H
Rigneault
ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology , 08860 Barcelona, Spain.|ICREA , Passeig de Lluís Companys 23, 08010 Barcelona, Spain.
Niek F
NF
Van Hulst
ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology , 08860 Barcelona, Spain.|ICREA , Passeig de Lluís Companys 23, 08010 Barcelona, Spain.
María F
MF
García-Parajó
CNRS UMR5048, Centre de Biochimie Structurale , 29 rue de Navacelles, 34090 Montpellier, France.|INSERM U1054 , 34090 Montpellier, France.|Université Montpellier , 34090 Montpellier, France.
Emmanuel
E
Margeat
CNRS, Aix Marseille Université, Centrale Marseille, Institut Fresnel, UMR 7249, 13013Marseille, France.
Jérôme
J
Wenger
FRET; LDOS; dipole−dipole interaction; fluorescence enhancement; optical antenna; plasmonics