Dynamics of deterministically positioned single‐bond surface‐enhanced Raman scattering from DNA origami assembled in plasmonic nanogaps

Chikkaraddy, Rohit; Turek, Vladimir A.; Lin, Qianqi; Griffiths, Jack; Nijs, Bart de; Keyser, Ulrich F.; Baumberg, Jeremy J.

doi:10.1002/jrs.5997

Cited by 9 publications

(8 citation statements)

References 46 publications

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“…Other alternatives include exploiting DNA origami to place individual molecules at well-defined positions in nanocavities 48 , 49 or implementing nanolenses to increase the detected signal as well as the coupling to incoming lasers. 50 Alternative approaches rely on the design of hybrid dielectric–plasmonic structures, which exhibit modes characterized by much smaller losses than in plasmonic resonances.…”

Section: Discussionmentioning

confidence: 99%

Molecular Optomechanics Approach to Surface-Enhanced Raman Scattering

2022

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Conspectus Molecular vibrations constitute one of the smallest mechanical oscillators available for micro-/nanoengineering. The energy and strength of molecular oscillations depend delicately on the attached specific functional groups as well as on the chemical and physical environments. By exploiting the inelastic interaction of molecules with optical photons, Raman scattering can access the information contained in molecular vibrations. However, the low efficiency of the Raman process typically allows only for characterizing large numbers of molecules. To circumvent this limitation, plasmonic resonances supported by metallic nanostructures and nanocavities can be used because they localize and enhance light at optical frequencies, enabling surface-enhanced Raman scattering (SERS), where the Raman signal is increased by many orders of magnitude. This enhancement enables few- or even single-molecule characterization. The coupling between a single molecular vibration and a plasmonic mode constitutes an example of an optomechanical interaction, analogous to that existing between cavity photons and mechanical vibrations. Optomechanical systems have been intensely studied because of their fundamental interest as well as their application in practical implementations of quantum technology and sensing. In this context, SERS brings cavity optomechanics down to the molecular scale and gives access to larger vibrational frequencies associated with molecular motion, offering new possibilities for novel optomechanical nanodevices. The molecular optomechanics description of SERS is recent, and its implications have only started to be explored. In this Account, we describe the current understanding and progress of this new description of SERS, focusing on our own contributions to the field. We first show that the quantum description of molecular optomechanics is fully consistent with standard classical and semiclassical models often used to describe SERS. Furthermore, we note that the molecular optomechanics framework naturally accounts for a rich variety of nonlinear effects in the SERS signal with increasing laser intensity. Furthermore, the molecular optomechanics framework provides a tool particularly suited to addressing novel effects of fundamental and practical interest in SERS, such as the emergence of collective phenomena involving many molecules or the modification of the effective losses and energy of the molecular vibrations due to the plasmon–vibration interaction. As compared to standard optomechanics, the plasmonic resonance often differs from a single Lorentzian mode and thus requires a more detailed description of its optical response. This quantum description of SERS also allows us to address the statistics of the Raman photons emitted, enabling the interpretation of two-color correlations of the emerging photons, with potential use in the generation of nonclassical states of light. Current SERS experimental implementations in organic molecules and two-dimensional la...

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Section: Discussionmentioning

confidence: 99%

Molecular Optomechanics Approach to Surface-Enhanced Raman Scattering

2022

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“…Furthermore, various kinds of nanoparticles can be arranged on the nanoscale to create sophisticated plasmonic nanostructures and to perform SERS − and surface-enhanced fluorescence (SEF) , measurements. Past examples of such structures include different platforms to form dimers of spherical particles, ,,,− dimers of Au nanostars, bowtie antennas, bimetallic nanostructures, , DNA origami nanocavities, , and plasmonic nanostructures consisting of three or more spherical particles. ,,, While DNA origami-based nanoantennas with larger interparticle gaps in the range of 10–30 nm are required for SEF, SERS requires small gaps below about 5 nm to provide strong signal enhancement. Consequently, DNA origami-based SM SERS measurements have mainly focused on small molecules such as organic dyes that can be placed in small interparticle gaps either by random adsorption or by DNA conjugation.…”

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confidence: 99%

A Versatile DNA Origami-Based Plasmonic Nanoantenna for Label-Free Single-Molecule Surface-Enhanced Raman Spectroscopy

et al. 2021

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DNA origami technology allows for the precise nanoscale assembly of chemical entities that give rise to sophisticated functional materials. We have created a versatile DNA origami nanofork antenna (DONA) by assembling Au or Ag nanoparticle dimers with different gap sizes down to 1.17 nm, enabling signal enhancements in surface-enhanced Raman scattering (SERS) of up to 1011. This allows for single-molecule SERS measurements, which can even be performed with larger gap sizes to accommodate differently sized molecules, at various excitation wavelengths. A general scheme is presented to place single analyte molecules into the SERS hot spots using the DNA origami structure exploiting covalent and noncovalent coupling schemes. By using Au and Ag dimers, single-molecule SERS measurements of three dyes and cytochrome c and horseradish peroxidase proteins are demonstrated even under nonresonant excitation conditions, thus providing long photostability during time-series measurement and enabling optical monitoring of single molecules.

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“…The results confirm the role of picocavities in this nanogap geometry, allowing observation of SERS signatures from individual vibrating bonds. [ 8 ]…”

Section: Methodsmentioning

confidence: 99%

“…The results confirm the role of picocavities in this nanogap geometry, allowing observation of SERS signatures from individual vibrating bonds. [8] Litti, Liz-Marzán, et al propose a protocol, with an associated smartphone application (known as SER-STEM), which enables users to determine the average SERS intensity per nanoparticle from transmission electron microscopy (TEM) and SERS data. As a proof of concept, they demonstrated the method for Au nanostars and nanorods, carrying four different Raman reporters, and implemented in the SERSTEM App, which is publicly available from an open-source platform.…”

Section: Theorymentioning

confidence: 99%