DNA Origami‐Guided Assembly of the Roundest 60–100 nm Gold Nanospheres into Plasmonic Metamolecules

Abstract

DNA origami can provide programmed information to guide the selfassembly of gold nanospheres (Au NSs) into higher-order supracolloids. Molecularly precise and truly 2D/3D integration of Au NSs is possible using DNA origami-enabled assembly, and the resulting assemblies have potential applications in plasmonics and metamaterials. However, the relatively small size (<60 nm) and randomly faceted Au NSs that have been used thus far in DNA origami-enabled assembly have limited their nanophotonic applications. Here, the robust self-assembly of the 60-100 nm roundest Au NSs into metamolecular assemblies using 3D DNA origami is described. These Au NSs are successfully conjugated with DNA oligonucleotides and are therefore stable at high salt concentrations even without backfilling using organic ligands. The roundest Au NSs are successfully assembled into supracolloidal metamolecules and chains via 3D DNA origami. These plasmonic metamolecules and chains display strong electric and unnatural magnetic resonances that can be deterministically controlled.

Recent advances in plasmonic nanocavities for single-molecule spectroscopy

“…Second, it employs colloidal MNPs, which are less prone to surface defects and can be fabricated with higher uniformity than evaporated metallic structures leading to improved reproducibility and performance. 65 Finally, with this technique, a single-photon emitter can be routinely placed in the hotspots of MNPs with nanometer precision, a key factor in controlling the coupling between single molecules and nanocavities. 66,67 These advantages were initially exploited to revisit experiments on uorescence-enhanced spectroscopy 68,69 and SERS [70][71][72] using dimer nanocavities made of Au or Ag, achieving enhancement values outperforming in some cases those obtained by using nanocavities fabricated with more complex top-down lithographic techniques.…”

Photothermal conversion of SiO2@Au nanoparticles mediated by surface morphology of gold cluster layer

“…In contrast, bottom-up methods based on chemical assembly offer a cheap, fast and exible technology for preparing close-packed colloidal particles as LSPR substrate. [34][35][36] Guillermo et al found that laser irradiation at high energy produced a near-eld enhancement at the interparticle gaps, causing the local temperature to increase high enough to melt the tip of the gold nanorod. 36 This further proves that the coupling effect brought by the gap between the particles can enhance its photothermal performance.…”

Light‐Directed Soft Mass Migration for Micro/Nanophotonics

“…Consequently, various 2D and 3D plasmonic metamolecules and optical antennas can be developed by AFM assembly . Recent advances in a chemical route for the synthesis of the roundest AuNPs have further improved the accuracy (a resolution of a few nanometers) and reliability of this AFM assembly method . Benefitting from this technological advance in AFM assembly, 32 roundest 60 nm Au nanospheres (NSs) were individually positioned at differently programmed locations.…”