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Improved Glass Surface Passivation for Single-Molecule Nanoarrays
1Department of Mechanical Engineering and ‡Department of Applied Physics and Applied Mathematics, Columbia University , New York, New York 10027, United States.
Langmuir : the ACS Journal of Surfaces and Colloids
|September 14, 2016
Summary
A new method using hydrogen silsesquioxane (HSQ) improves surface passivation for single-molecule fluorescence, significantly reducing nonspecific adsorption and enhancing signal clarity for biomolecular studies.
Area of Science:
- Biophysics
- Surface Chemistry
- Nanotechnology
Background:
- Single-molecule fluorescence techniques offer high-resolution insights into biomolecular interactions.
- Nonspecific adsorption of biomolecules to surfaces is a major challenge, often addressed by poly(ethylene glycol) (PEG) brushes.
- Existing passivation methods like PEG brushes and Tween-20 have limitations, including defects and cell incompatibility.
Purpose of the Study:
- To develop a versatile and effective method for improving surface passivation in single-molecule fluorescence experiments.
- To overcome the limitations of current passivation techniques, particularly concerning surface impurities and probe molecule adsorption.
- To enhance the signal-to-background ratio (SBR) for imaging single molecules on patterned nanostructures.
Main Methods:
- Spin-coating a thin film of hydrogen silsesquioxane (HSQ) on glass coverslips, followed by thermal curing.
- Utilizing HSQ to cover surface impurities, thereby minimizing defects in subsequent poly(ethylene glycol) (PEG) brush formation.
- Applying the improved passivation to single-molecule nanoarrays of streptavidin anchored to electron-beam lithography (EBL)-patterned AuPd nanodots.
Main Results:
- The HSQ layer effectively masked surface impurities, leading to more uniform PEG brush formation.
- Nonspecific adsorption was significantly reduced on HSQ-treated surfaces, comparable to Tween-20 treatment.
- A ~4-fold improvement in the fluorescence signal to background ratio (SBR) was achieved compared to PEG directly on glass.
Conclusions:
- Hydrogen silsesquioxane (HSQ) provides a robust and versatile surface passivation strategy for single-molecule fluorescence.
- This method enhances the quality of single-molecule imaging by reducing background noise and improving signal detection.
- The improved passivation enables clearer visualization of ordered single-molecule arrays on nanostructured surfaces.
