Metallic-nanoparticles-enhanced fluorescence from individual micron-sized aerosol particles on-the-fly

Area of Science:

• Spectroscopy
• Nanomaterials Science
• Aerosol Science

Background:

• Single-particle analysis is crucial for understanding aerosol composition and behavior.
• Metallic nanoparticles (MNPs) can influence optical properties of surrounding materials.
• Fluorescence spectroscopy offers sensitive detection of various substances.

Purpose of the Study:

• To investigate the effect of metallic nanoparticles (MNPs) on the fluorescence spectra of individual aerosol particles.
• To explore the potential of MNP-aerosol interactions for enhancing spectroscopic sensor performance.

Main Methods:

• Generated aerosols of polystyrene latex (PSL) spheres and protein clusters (tryptophan, ovalbumin) embedded with or coated by MNPs.
• Acquired fluorescence spectra from single aerosol particles on-the-fly using 266 nm and 355 nm excitation.
• Varied MNP concentration to observe its effect on fluorescence intensity.

Main Results:

• Observed both fluorescence enhancement and quenching depending on MNP concentration and material.
• Demonstrated that MNPs can significantly alter the fluorescence signal of PSL spheres and protein aerosols.
• Showed a concentration-dependent relationship between MNPs and fluorescence intensity.

Conclusions:

• Metallic nanoparticles can modulate the fluorescence of aerosol particles.
• Optimizing MNP properties (material, size, spacing) is key to enhancing fluorescence signals.
• This approach holds promise for improving the sensitivity of single-particle spectroscopic sensors.