Autonomous DNA Nanoswitch Encodes Quantum-Yield Oscillations for Time-Resolved Single-Molecule Readout

Area of Science:

• Nanotechnology
• Biophysics
• Materials Science

Background:

• Precise control of fluorescence quantum yield is crucial for molecular imaging and ultrasensitive detection.
• Existing plasmon-fluorophore studies often use fixed gaps or ensemble averages, limiting real-time tuning of individual emitters.
• Autonomous, real-time tuning via nanometal surface energy transfer is largely unexplored.

Purpose of the Study:

• To introduce an autonomous DNA-metallic nanoswitch for dynamic modulation of single emitter quantum yield.
• To explore real-time tuning of fluorescence via nanometal surface energy transfer at the single-emitter level.
• To provide a versatile platform for time-resolved single-molecule readout.

Main Methods:

• Development of a DNA-metallic nanoswitch utilizing programmable DNA hybridization.
• Dynamic modulation of the distance between a single emitter and a gold nanoparticle.
• Utilizing nanometal surface energy transfer to control fluorescence quantum yield.

Main Results:

• The nanoswitch autonomously modulates quantum yield by shuttling dyes between "off" (r < 1 nm) and "on" (r > 4 nm) states.
• Reversible oscillations in fluorescence follow the characteristic ~1/d^4 distance dependence.
• Robust self-blinking trajectories and time-domain metrics were achieved even in high-background conditions.

Conclusions:

• The DNA-metallic nanoswitch offers autonomous, nanometer-scale positioning and DNA addressability.
• This technology deepens the understanding of metal-fluorophore coupling.
• It provides a versatile platform for advanced molecular imaging and diagnostics.