Re-direction of surface plasmon-coupled emission using metallic nanoparticles

Area of Science:

• Optics and Photonics
• Materials Science
• Biomedical Engineering

Background:

• Surface plasmon-coupled emission (SPCE) arises from fluorophore coupling with plasmonic states near metal films.
• SPCE typically exhibits narrow angular emission from the bottom, limiting its use in standard assay instruments.
• Current SPCE detection methods require specialized prism-based setups, hindering high-throughput screening.

Purpose of the Study:

• To demonstrate a method for redirecting SPCE into the free-space direction.
• To enable top-reading detection of SPCE for broader instrument compatibility.
• To expand the utility of plasmon-controlled fluorescence (PCF) in diagnostic and assay development.

Main Methods:

• Utilizing a thin layer of silver particles to modify SPCE emission patterns.
• Investigating the redirection of plasmon-coupled emission using plasmonic nanoparticles.
• Analyzing the angular distribution of fluorescence emission after modification with silver particles.

Main Results:

• SPCE was successfully re-directed upwards into the free-space direction using a layer of silver particles.
• This redirection enables fluorescence measurements from both the top and bottom of the sample.
• The modified emission pattern overcomes the limitations of bottom-emission-only detection.

Conclusions:

• Silver particles can effectively redirect SPCE, enhancing its applicability.
• This technique facilitates top-reading fluorescence measurements, compatible with standard assay platforms.
• The developed method broadens the scope of plasmon-controlled fluorescence assays for diagnostics and screening.