DNA Origami Optical Circuits: Korea University’s 70-Molecule Sensor

인더스트리뉴스 (Industry News) South Korea

Overview

Researchers at Korea University have developed an optical nanocircuit using DNA origami to precisely position gold nanoparticles, enabling the detection of optical signals from approximately 70 dye molecules. This approach requires roughly 100 times fewer molecules than single gold nanoparticle structures to achieve similar signal levels, offering a path toward ultra-sensitive optical sensors.

In Depth

Key Findings

A research team led by Professor Seung-woo Lee from Korea University’s KU-KIST Graduate School and Department of Convergence Energy Engineering has successfully implemented an optical nanocircuit using “DNA origami” technology. The team demonstrated that by precisely arranging gold nanoparticles, they could detect optical signals from approximately 70 dye molecules (YOYO-3). In comparison, a single gold nanoparticle structure required approximately 6,400 dye molecules to produce a similar signal level.

Technical Details

The team utilized the base-pairing properties of DNA to create a hollow cylindrical nanostructure with a diameter of approximately 30 nanometers and a height of approximately 20 nanometers, constructed from three layers of DNA. Smooth gold nanoparticles were then attached to specific positions on this structure, with dye molecules bound to the DNA and placed between the particles.

The researchers also tested a circuit consisting of three gold nanoparticles of different sizes. This configuration resulted in a more distinct light resonance. The resonance quality factor (Q), which measures the clarity of the resonance response to specific wavelengths of light, was approximately 19.2—significantly higher than the 4 to 10 range observed in similar existing gold nanoparticle structures.

Background & Context

When gold nanoparticles are placed in close proximity, the electric field of light concentrates in the narrow gap between them. Placing dye molecules in this gap strengthens the interaction between light and the molecules, allowing for the observation of minute optical signals. However, because the response changes drastically with slight variations in particle shape or spacing, precise structural control has been a primary technical challenge.

Significance & Outlook

This research, conducted in collaboration with Professor William Si of Harvard University and Professor Shelley Wickham of the University of Sydney, demonstrates that DNA structures can be used to control the positioning of nanoparticles and molecules to modulate light resonance and molecular signals. The findings are expected to be applied to optical sensors for analyzing small quantities of molecules and studies on light-molecule interactions. The study was published online in Science Advances on October 7 and supported by the Ministry of Science and ICT, the Ministry of Health and Welfare (KUCRF), the Australian Research Council (ARC), and Korea University.

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