title: DNA-templated nanoantennas for single-molecule detection at elevated concentrations.
abstract: The dynamic concentration range is one of the major limitations of single-molecule fluorescence techniques. We show how bottom-up nanoantennas enhance the fluorescence intensity in a reduced hotspot, ready for biological applications. We use self-assembled DNA origami structures as a breadboard where gold nanoparticle (NP) dimers are positioned with nanometer precision. A maximum of almost 100-fold intensity enhancement is obtained using 100-nm gold NPs within a gap of 23 nm between the particles. The results obtained are in good agreement with numerical simulations. Due to the intensity enhancement introduced by the nanoantenna, we are able to perform single-molecule measurements at concentrations as high as 500 nM, which represents an increment of 2 orders of magnitude compared to conventional measurements. The combination of metallic NPs with DNA origami structures with docking points for biological assays paves the way for the development of bottom-up inexpensive enhancement chambers for single-molecule measurements at high concentrations where processes like DNA sequencing occur.
authors.affiliation: Technische Universität Braunschweig, Physical and Theoretical Chemistry—NanoBioScience, Hans-Sommer-Strasse 10, 38106 Braunschweig, Germany. g.acuna@tu-bs.de
authors.forename: Guillermo P
authors.initials: GP
authors.lastname: Acuna
authors.forename: Phil
authors.initials: P
authors.lastname: Holzmeister
authors.forename: Friederike M
authors.initials: FM
authors.lastname: Möller
authors.forename: Susanne
authors.initials: S
authors.lastname: Beater
authors.forename: Birka
authors.initials: B
authors.lastname: Lalkens
authors.forename: Philip
authors.initials: P
authors.lastname: Tinnefeld
mesh_terms: D001360:Avidin / Q000737:chemistry; D001710:Biotin / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D019281:Dimerization; D005456:Fluorescent Dyes / Q000737:chemistry / Q000494:pharmacology; D006046:Gold / Q000737:chemistry; D007091:Image Processing, Computer-Assisted; D053768:Metal Nanoparticles / Q000737:chemistry; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence / Q000379:methods*; D008962:Models, Theoretical; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D013050:Spectrometry, Fluorescence
chemical_list: D005456:Fluorescent Dyes; C093483:neutravidin; D001360:Avidin; D001710:Biotin; D006046:Gold; D004247:DNA