Self-Assembled Active Plasmonic Waveguide with a Peptide-Based Thermomechanical Switch.

Area of Science:

• Nanotechnology
• Plasmonics
• Biophysics

Background:

• Plasmonic waveguides guide electromagnetic energy below the optical diffraction limit.
• Current fabrication and readout methods are complex, often requiring lithography or near-field optical techniques.

Purpose of the Study:

• To develop a switchable plasmonic waveguide with simple spectroscopic excitation and readout.
• To enable bulk solution applications for nanoscale light manipulation.

Main Methods:

• Assembled switchable plasmonic waveguides from gold nanoparticles (AuNPs) on DNA origami structures.
• Utilized fluorescent dyes for spectroscopic excitation and energy transfer readout.
• Employed a thermoresponsive peptide to reversibly switch waveguide transmittance by repositioning an AuNP.
• Achieved high-yield bulk fabrication using silica particles as solid supports.

Main Results:

• Demonstrated energy transfer beyond multicolor Förster resonance energy transfer (FRET) range and below the Abbé limit.
• Showcased reversible switching of waveguide transmittance.
• Established a method for high-yield bulk fabrication of these waveguides.

Conclusions:

• Developed a novel, switchable plasmonic waveguide system using DNA origami and AuNPs.
• Enabled simple spectroscopic readout and bulk solution applications for nanoscale light manipulation.
• Paved the way for plasmonic waveguides as sub-diffraction limit light-focusing and polarizing elements.