Metal-Enhanced Fluorescence Lifetime Imaging and Spectroscopy on a Modified SERS Substrate

Area of Science:

• Biophotonics
• Nanotechnology
• Surface Chemistry

Background:

• Metal-enhanced fluorescence (MEF) shows great promise but is hindered by challenges in fabricating reproducible substrates.
• Existing MEF substrates lack standardization, limiting their application in real-world scenarios and commercial use.
• Reproducibility in fluorescence intensity enhancement and lifetime changes is a key challenge for MEF applications.

Purpose of the Study:

• To develop a standardized metal-enhanced fluorescence (MEF) substrate with improved reproducibility and sensitivity.
• To address the fabrication challenges associated with current MEF substrates.
• To create a versatile platform for various sensing applications.

Main Methods:

• Modification of commercially available surface-enhanced Raman spectroscopy (SERS) substrates by coating with silver nanoparticles.
• Assembly of a monolayer of streptavidin conjugated Alexa-647 on biotinylated-glass and the newly developed MEF substrates.
• Characterization using fluorescence intensity measurements and fluorescence lifetime imaging.

Main Results:

• A >50-fold increase in fluorescence intensity was observed for Alexa-647 on the MEF substrate compared to glass.
• A significant reduction in fluorescence lifetime and enhanced photostability of Alexa-647 were detected on the MEF substrate.
• Successful fluorescence lifetime imaging demonstrated the substrate's capability.

Conclusions:

• The developed MEF substrate, based on modified SERS platforms, offers enhanced performance and reproducibility.
• This standardized MEF substrate provides a robust platform for sensitive and reliable fluorescence-based sensing.
• The study paves the way for broader adoption of MEF technology in diverse sensing applications.