Raman Enhancement of Nanoparticle Dimers Self-Assembled Using DNA Origami Nanotriangles.
Sergio KogikoskiKosti TapioRobert Edler von ZanderPeter SaalfrankIlko BaldPublished in: Molecules (Basel, Switzerland) (2021)
Surface-enhanced Raman scattering is a powerful approach to detect molecules at very low concentrations, even up to the single-molecule level. One important aspect of the materials used in such a technique is how much the signal is intensified, quantified by the enhancement factor (EF). Herein we obtained the EFs for gold nanoparticle dimers of 60 and 80 nm diameter, respectively, self-assembled using DNA origami nanotriangles. Cy5 and TAMRA were used as surface-enhanced Raman scattering (SERS) probes, which enable the observation of individual nanoparticles and dimers. EF distributions are determined at four distinct wavelengths based on the measurements of around 1000 individual dimer structures. The obtained results show that the EFs for the dimeric assemblies follow a log-normal distribution and are in the range of 106 at 633 nm and that the contribution of the molecular resonance effect to the EF is around 2, also showing that the plasmonic resonance is the main source of the observed signal. To support our studies, FDTD simulations of the nanoparticle's electromagnetic field enhancement has been carried out, as well as calculations of the resonance Raman spectra of the dyes using DFT. We observe a very close agreement between the experimental EF distribution and the simulated values.
Keyphrases
- single molecule
- energy transfer
- density functional theory
- living cells
- atomic force microscopy
- molecular dynamics
- monte carlo
- raman spectroscopy
- photodynamic therapy
- gold nanoparticles
- label free
- quantum dots
- molecular dynamics simulations
- high resolution
- sensitive detection
- high frequency
- small molecule
- circulating tumor
- case control
- crystal structure
- nucleic acid