Formation of Linear Plasmonic Heterotrimers Using Nanoparticle Docking to DNA Origami Cages

Area of Science:

• Nanotechnology
• Materials Science
• Biophysics

Background:

• Fabricating complex assemblies from plasmonic nanoparticles (NPs) with specific collective properties is challenging.
• Existing DNA-directed self-assembly methods often result in variable gap sizes and shapes due to flexible DNA strands and NP polydispersity.

Purpose of the Study:

• To develop a novel strategy, docking to DNA origami cages (D-DOC), for precise geometric arrangement of spherical NPs into linear heterotrimers.
• To overcome the limitations of variability in gap sizes and shapes inherent in current self-assembly techniques.

Main Methods:

• Utilized a D-DOC strategy where NPs bind to the interior or opening of 3D DNA origami cages, using multiple capture strands for tethering.
• Employed a multistep assembly process: encapsulating one NP inside a cage, followed by binding two additional NPs to the cage openings.
• Incorporated shape complementarity for enhanced NP confinement within the DNA cage structure.

Main Results:

• Achieved precise geometrical arrangement of NPs in a linear heterotrimer with minimal variability in bond angles and gap sizes.
• Demonstrated strong plasmonic coupling through UV-vis absorption and surface-enhanced Raman scattering (SERS) measurements.
• Experimental results aligned with predictions from electrodynamic simulations, confirming assembly precision.

Conclusions:

• The D-DOC method offers a highly precise approach for self-assembling plasmonic nanoparticles into complex 3D structures.
• This technique holds significant potential for advancing applications in biomolecular sensing, SERS and fluorescence spectroscopies, and energy harvesting.