Quantitative Single-Molecule Surface-Enhanced Raman Scattering by Optothermal Tuning of DNA Origami-Assembled Plasmonic Nanoantennas

Abstract

DNA origami is a powerful approach for assembling plasmonic nanoparticle dimers and Raman dyes with high yields and excellent positioning control. Here we show how optothermal-induced shrinking of a DNA origami template can be employed to control the gap sizes between two 40 nm gold nanoparticles in a range from 1 to 2 nm. The high field confinement achieved with this optothermal approach was demonstrated by detection of surface-enhanced Raman spectroscopy (SERS) signals from single molecules that are precisely placed within the DNA origami template that spans the nanoparticle gap. By comparing the SERS intensity with respect to the field enhancement in the plasmonic hot-spot region, we found good agreement between measurement and theory. Our straightforward approach for the fabrication of addressable plasmonic nanosensors by DNA origami demonstrates a path toward future sensing applications with single-molecule resolution.

DNA‐Mediated Assembly of Gold Nanoparticles and Applications in Bioanalysis

“…One strategy is based on well‐defined DNA scaffolds consisting of numerous building blocks like tiles onto which nanoparticles would be organized . The other well‐developed strategy recently is using DNA origami as the template to achieve various assembled patterns . The conventional tile‐based strategies typically involve the construction of DNA tiles and subsequent self‐assembly of the nanoparticles into tiled arrays.…”

“…a, scale bar, 40 nm. Reproduced with permission from reference . Copyright 2016, American Chemical Society; b, scale bar, 50 nm.…”

“…Compared with simple hybridization of the strands modifying the nanoparticles, DNA origami as templates could lead to more precise spatial control of the assemblies. Lohmüller and colleagues have developed the AuNP dimer platform on the basis of a DNA origami template for single‐molecule assay . The gap between the 40‐nm AuNPs was reduced by optothermal‐induced shrinking of the DNA origami template, displaying a change of the SERS signal for detection of single molecules as shown in Figure A.…”

“…[21][22][23] The other well-developed strategy recently is using DNA origami as the template to achieve variousa ssembled patterns. [3,[24][25][26] The conventionalt ile-based strategies typically involve the construction of DNA tiles and subsequents elf-assembly of the nanoparticles into tiled arrays. In turn, the DNA origami uses av ersatile "one-pot" process to generate the scaffold.…”

“…3D DNAdriven AuNP crystals have also been constructed without any base pairing in adrying-mediated self-assembly process. [17,68] [24].Copyright 2016, American Chemical Society;b ,scale bar,50nm. Reproduced with permission from reference [39].Copyright 2017,American Chemical Society; c,d, 60 nm core and 15 nm satellite nanoparticles.…”