Gold nanorod assemblies: the roles of hot-spot positioning and anisotropy in plasmon coupling and SERS

Priyanka Dey*, Verena Baumann, Jessica Rodríguez-Fernández

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

36 Downloads (Pure)


Plasmon-coupled colloidal nanoassemblies with carefully sculpted “hot-spots” and intense surface-enhanced Raman scattering (SERS) are in high demand as photostable and sensitive plasmonic nano-, bio-, and chemosensors. When maximizing SERS signals, it is particularly challenging to control the hot-spot density, precisely position the hot-spots to intensify the plasmon coupling, and introduce the SERS molecule in those intense hot-spots. Here, we investigated the importance of these factors in nanoassemblies made of a gold nanorod (AuNR) core and spherical nanoparticle (AuNP) satellites with ssDNA oligomer linkers. Hot-spot positioning at the NR tips was made possible by selectively burying the ssDNA in the lateral facets via controlled Ag overgrowth while retaining their hybridization and assembly potential at the tips. This strategy, with slight alterations, allowed us to form nanoassemblies that only contained satellites at the NR tips, i.e., directional anisotropic nanoassemblies; or satellites randomly positioned around the NR, i.e., nondirectional nanoassemblies. Directional nanoassemblies featured strong plasmon coupling as compared to nondirectional ones, as a result of strategically placing the hot-spots at the most intense electric field position of the AuNR, i.e., retaining the inherent plasmon anisotropy. Furthermore, as the dsDNA was located in these anisotropic hot-spots, this allowed for the tag-free detection down to ~10 dsDNA and a dramatic SERS enhancement of ~1.6 × 108 for the SERS tag SYBR gold, which specifically intercalates into the dsDNA. This dramatic SERS performance was made possible by manipulating the anisotropy of the nanoassemblies, which allowed us to emphasize the critical role of hot-spot positioning and SERS molecule positioning in nanoassemblies.

Original languageEnglish
Article number942
Number of pages16
Issue number5
Publication statusPublished - 14 May 2020


  • anisotropy
  • core
  • directional assembly
  • DNA linker
  • gold nanorods
  • hot-spot positioning
  • satellite nanoassembly
  • SERS molecule positioning
  • silver coating


Dive into the research topics of 'Gold nanorod assemblies: the roles of hot-spot positioning and anisotropy in plasmon coupling and SERS'. Together they form a unique fingerprint.

Cite this