Quantum Well-Enhanced Plasmonic Substrate to Enhance Spontaneously Blinking Fluorescence for Single-Molecule...

Area of Science:

• Nanotechnology
• Biophysics
• Materials Science

Background:

• Single-molecule localization microscopy (SMLM) requires bright and stable fluorophores for high-resolution imaging.
• Conventional plasmonic substrates enhance fluorescence but can be limited in their enhancement capabilities.
• Improving fluorophore blinking characteristics is crucial for advancing SMLM precision and density.

Purpose of the Study:

• To develop and characterize a novel Quantum Well (QW)-enhanced plasmonic substrate for improved SMLM.
• To investigate the underlying mechanisms of fluorescence enhancement by the QW-plasmonic substrate.
• To demonstrate the application of this substrate in biological imaging, specifically for EGFR in cancer cells.

Main Methods:

• Fabrication of a plasmonic substrate comprising InGaN QWs and Aluminum nanoparticles.
• Characterization of plasmonic and fluorescence enhancement properties.
• Application of the substrate in SMLM imaging of phosphorylated epidermal growth factor receptors (EGFRs) in A549 lung cancer cells.

Main Results:

• The QW-enhanced plasmonic substrate significantly increased fluorophore blinking intensity and event frequency.
• Enhanced local surface plasmon resonance due to charge transfer resonances and interactions between QWs and nanoparticles.
• Achieved improved SMLM image resolution and reduced excitation power requirements.
• Successfully imaged EGFR in cancer cells, enabling quantitative analysis of tyrosine kinase inhibition.

Conclusions:

• The developed InGaN QW-enhanced plasmonic substrate offers multiple fluorescence enhancement effects for SMLM.
• This technology improves localization precision and density, enabling advanced biological imaging applications.
• The substrate provides a promising platform for reducing excitation power in SMLM while maintaining high resolution.