Optically Active AuNR@Ag Core-Shell Nanoparticles and Hierarchical Assembly via DNA-Mediated Surface Chemistry

Area of Science:

• Plasmonics
• Nanotechnology
• Biomaterials

Background:

• Controlling chiroptical activity and self-assembly of plasmonic metal nanoparticles (MNPs) is crucial but challenging.
• Existing methods for DNA functionalization of MNPs often lead to embedding, not surface encoding.

Purpose of the Study:

• To fabricate anisotropic bimetallic gold nanorod@silver core-shell nanoparticles (AuNR@Ag NPs) with DNA molecules for controlled chiroptical properties.
• To investigate the plasmonic chiroptical properties of individual AuNR@Ag NPs and their assemblies.
• To explore DNA's role in surface chemistry and hierarchical self-assembly.

Main Methods:

• In situ fabrication of AuNR@Ag NPs using DNA-capped gold nanorods (AuNRs) as seeds for silver shell growth.
• Studying the dynamic DNA desorption and re-adsorption process during shell overgrowth.
• Characterizing plasmonic chiroptical properties of nanoparticles and their assemblies.

Main Results:

• AuNR@Ag NPs were successfully synthesized with DNA molecules encoded on their surfaces via an in situ dynamic process.
• Individual AuNR@Ag NPs exhibited plasmonic chiroptical activities.
• Chiroptical responses were tunable by altering the shape anisotropy of the building blocks.
• DNA on NP surfaces facilitated hierarchical assembly into nanostructures with distinct chiral optical responses.

Conclusions:

• The in situ DNA-mediated surface chemistry enables tunable plasmonic chiroptical properties in individual AuNR@Ag NPs.
• This approach provides a pathway for controlled hierarchical self-assembly of chiral plasmonic nanostructures.
• The findings offer significant potential for fundamental and technological advancements in plasmonics and nanotechnology.