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Updated: Jul 2, 2025
09:33
Monitoring Conformational Dynamics of Single Unmodified Proteins using Plasmonic Nanotweezers
Published on: March 21, 2025
707
Label-Free Tracking of Proteins through Plasmon-Enhanced Interference
Matthew Peters1,2, Declan McIntosh1, Alexandra Branzan Albu1
1Department of Electrical Engineering, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada.
ACS Nanoscience Au
|February 26, 2024
Summary
Surface plasmon-enhanced imaging tracks small, unmodified proteins in real time. This breakthrough allows for rapid protein characterization and interaction studies with minimal sample preparation.
Area of Science:
- Biophysics
- Nanotechnology
- Analytical Chemistry
Background:
- Interferometric imaging typically requires larger proteins (>30 kDa) due to Rayleigh scattering limitations.
- Observing and characterizing smaller, unmodified biomolecules in solution remains a significant analytical challenge.
Purpose of the Study:
- To develop a method for real-time tracking and characterization of smaller, unmodified proteins.
- To overcome the limitations of Rayleigh scattering in biomolecular imaging.
Main Methods:
- Utilized interference imaging enhanced by surface plasmons launched at a nanoaperture in a metal film.
- Performed real-time image tracking of diffusing proteins.
- Applied power spectral density and noise amplitude analysis to trapped proteins.
Main Results:
- Successfully tracked unmodified proteins down to 14 kDa in real time.
- Quantified diffusion rates, observing slower diffusion for larger proteins.
- Obtained protein information through analysis of trapped molecules.
Conclusions:
- Surface plasmon-enhanced interferometric imaging enables detection of smaller proteins than previously possible.
- This technique offers rapid protein characterization with minimal sample preparation.
- Paves the way for real-time analysis of protein interactions.
