Making gold nanoparticles fluorescent for simultaneous absorption and fluorescence detection on the single particle...

Area of Science:

• Nanotechnology
• Materials Science
• Optical Physics

Background:

• Gold nanoparticles (NPs) are widely studied for their unique optical properties.
• Developing stable and bright fluorescent nanomaterials is crucial for advanced sensing and imaging.
• Existing fluorescent probes often suffer from photobleaching and limited stability.

Purpose of the Study:

• To develop a simple method for creating fluorescent individual gold nanoparticles.
• To characterize the fluorescence properties and stability of these gold nanoparticles.
• To propose and validate the use of these fluorescent gold nanoparticles as calibration standards for simultaneous optical detection techniques.

Main Methods:

• Synthesis of 20 nm gold nanoparticles.
• Characterization of fluorescence quantum yield and photostability in glycerol and water.
• Experimental demonstration of simultaneous fluorescence and photothermal absorption detection.
• Validation of axial position shift for simultaneous signal detection.

Main Results:

• Achieved fluorescence in individual 20 nm gold nanoparticles with a quantum yield of approximately 10^-6.
• Demonstrated long-term bright fluorescence under moderate excitation.
• Confirmed fluorescence stability upon solvent exchange from glycerol to water.
• Experimentally verified the predicted axial shift between fluorescence and absorption signals.

Conclusions:

• A straightforward method for producing fluorescent gold nanoparticles is presented.
• These fluorescent gold nanoparticles serve as effective calibration standards for multimodal optical detection.
• The ability for simultaneous absorption and fluorescence detection offers potential for multidimensional tracking and screening.