‘Squeezed’ interparticle properties for plasmonic coupling and SERS characteristics of duplex DNA conjugated/linked gold nanoparticles of homo/hetero-sizes

Abstract

The formation of interparticle duplex DNA conjugates with gold nanoparticles constitutes the basis for interparticle plasmonic coupling responsible for surface-enhanced Raman scattering signal amplification, but understanding of its correlation with interparticle spatial properties and particle sizes, especially in aqueous solutions, remains elusive. This report describes findings of an investigation of interparticle plasmonic coupling based on experimental measurements of localized surface plasmon resonance and surface enhanced Raman scattering characteristics for gold nanoparticles in aqueous solutions upon introduction of interparticle duplex DNA conjugates to define the interparticle spatial properties. Theoretical simulations of the interparticle optical properties and electric field enhancement based on a dimer model have also been performed to aid the understanding of the experimental results. The results have revealed a 'squeezed' interparticle spatial characteristic in which the duplex DNA-defined distance is close or shorter than A-form DNA conformation, which are discussed in terms of the interparticle interactions, providing fresh insight into the interparticle double-stranded DNA-defined interparticle spatial properties for the design of highly-sensitive nanoprobes in solutions for biomolecular detection.

Decoration of Nanofibrous Paper Chemiresistors with Dendronized Nanoparticles toward Structurally Tunable Negative‐Going Response Characteristics to Human Breathing and Sweating

“…The DMol3 tool and Amorphous cell from Accelrys Materials Studio 6.0 was used to build the interparticle interaction models. The simulation of the optical absorption and the enhancement of the electric field intensity in the dielectric environment surrounding AuNPs due to the effect of their localized surface plasmon resonances was performed using the MNPBEM toolbox based on the boundary element method, which has been demonstrated in our recent work on dimers of interparticle‐linked gold nanoparticles . A dimer of Au NPs with specific core sizes and a shell thickness defined by deSG‐SS (1.9 nm) and deLG‐SS (2.4 nm) was used.…”

Assessing Plasmonic Nanoprobes in Electromagnetic Field Enhancement for SERS Detection of Biomarkers

“…For example, magnetic MnZn ferrite NPs decorated with Au or Ag atoms or shells on the surface (M@Au or M@Ag) function as effective nanoprobes for SERS detection of double-strand DNA (dsDNA)-linked M@Au or M@Ag NPs and Au NPs [4,15]. The "hot-spot" electromagnetic field enhancement of the dsDNA-linked NPs was also supported by theoretical simulation [16] in terms of the effective thickness of DNA layers on an NP dimer model. The Au and magnetic core@Au shell strategy has also been demonstrated to be viable for SERS and electrochemical detection of anticancer drug interactions with DNAs [17,18].…”

Localized Surface Plasmon Resonances with Spherical Metallic Nanoparticles

“…Localized surface plasmon resonance (LSPR) is known to be responsible for the electrical intensity enhancement, which determines the optical and spectroscopy properties and has led to advances in several areas of the science and technology such as nano-scale sensing and modern analytical techniques based on spectroscopy applications [1][2][3][4][5][6][7][8][9]. These resonances, associated with noble metallic nanostructures, create sharp spectral absorption and scattering peaks as well as strong near-field enhancement of the electromagnetics.…”

“…These resonances, associated with noble metallic nanostructures, create sharp spectral absorption and scattering peaks as well as strong near-field enhancement of the electromagnetics. Among these is the detection of molecules interactions near the particle surface through shifts in the LSPR spectral peak, namely surfaceenhanced Raman spectroscopy (SERS) [3][4][5][6][7][8][9]. The formation of inter-particle of noble metallic nanoparticles in the dielectric medium constitutes the basis for inter-particle plasmonic coupling responsible for SERS signal amplification, but understanding of its correlation with inter-particle spatial properties, particle sizes and the refractive indices of the surrounded media, remains elusive.…”