Plasmon-mediated fluorescence with distance independence: from model to a biosensing application

Area of Science:

• Plasmonics
• Nanotechnology
• Biosensing

Background:

• Plasmon-mediated fluorescence biosensing typically shows distance-dependent signals.
• Precise distance control is often required, complicating biosensor design.

Purpose of the Study:

• To develop a distance-independent plasmon-mediated fluorescence biosensing strategy.
• To enhance signal stability and reliability in biosensing applications.

Main Methods:

• Utilized a full-coupling strategy to activate the entire plasmon coupling region.
• Employed fluorescent silica nanoparticles sized to match the coupling region for directional surface plasmon-coupled emission (SPCE).
• Confined fluorophore distribution within nanoparticles to optimize coupling effects.

Main Results:

• Achieved nearly distance-independent fluorescence response over a 0-30nm range.
• Demonstrated stable and detectable signals by filling the coupling dominant region with fluorophores.
• Successfully applied to immunoassays and DNA detection, yielding high and reliable signals.

Conclusions:

• Full-coupling SPCE overcomes distance-dependent signal variations in plasmon-mediated fluorescence.
• This method offers a robust and generalizable platform for chip-based biosensing without complex distance control architectures.
• Enables reliable nanoscale bioanalysis by mitigating issues with biomolecule orientation and conformation.