Raman identification of single nucleotides flowing through permeable plasmonic films

Area of Science:

• Nanotechnology
• Spectroscopy
• Biophysics

Background:

• Surface-Enhanced Raman Scattering (SERS) offers high sensitivity for molecular recognition, especially in biological contexts.
• Nanopore sequencing technology inspires new approaches for single-molecule analysis.
• Detecting individual molecules requires advanced techniques for high spatial and temporal resolution.

Purpose of the Study:

• To develop a novel plasmonic device for real-time, single-molecule detection in a flow-through configuration.
• To achieve angstrom spatial and microsecond temporal resolution for molecular analysis.
• To assess the feasibility of this device for polymer sequencing applications, such as DNA sequencing.

Main Methods:

• Fabrication of a permeable plasmonic film device.
• Utilizing electrophoresis for sequential delivery of single molecules through plasmonic hotspots.
• Real-time recording of Raman spectra with high light-matter coupling and ultrasmall plasmonic spots.
• Slowing molecule translocation for enhanced spectral capture.

Main Results:

• Successfully captured Raman spectra of individual nucleotides with a time resolution down to 20 μs.
• Achieved 89% discrimination accuracy at the single-molecule level.
• Demonstrated a spatial resolution on the order of a few nucleotides.

Conclusions:

• The developed plasmonic device enables high-resolution, real-time single-molecule detection.
• The device shows significant potential for advancing polymer sequencing technologies.
• This approach offers a promising new direction for rapid and accurate molecular identification.