Fluorescent Au@Ag core-shell nanoparticles with controlled shell thickness and Hg(II) sensing

Area of Science:

• Nanotechnology
• Materials Science
• Environmental Science

Background:

• Gold-silver (Au-Ag) core-shell nanoparticles offer tunable optical properties.
• Fluorescent nanomaterials are valuable for chemical sensing applications.
• Developing eco-friendly synthesis methods for nanomaterials is crucial.

Purpose of the Study:

• To synthesize Au-Ag core-shell nanoparticles using a naturally occurring fluorescent dipeptide.
• To investigate the controlled synthesis and optical properties of the Au-Ag core-shell nanomaterial.
• To evaluate the potential of the fluorescent Au-Ag core-shell nanoparticle for detecting toxic mercury (Hg(II)) ions.

Main Methods:

• Synthesis of Au-Ag core-shell nanoparticles in water at room temperature and pH 6.94 using β-Ala-Trp dipeptide.
• Characterization of the core-shell nanomaterial's optical properties, including fluorescence.
• Testing the selectivity and sensitivity of the fluorescent nanoparticle for Hg(II) ion detection in the presence of interfering metal ions.

Main Results:

• Successfully synthesized Au-Ag core-shell nanoparticles using an eco-friendly, reagent-free method.
• Demonstrated tunable optical properties and strong fluorescence in the synthesized nanomaterial.
• Achieved ultrasensitive detection of Hg(II) ions with a low detection limit of 9 nM, showing high selectivity over other bivalent metal ions.
• Confirmed the reusability of the Au-Ag core-shell nanoparticles for Hg(II) sensing.

Conclusions:

• The dipeptide-mediated synthesis provides an environmentally benign route to fluorescent Au-Ag core-shell nanoparticles.
• The synthesized fluorescent Au-Ag core-shell nanoparticles are effective and selective sensors for Hg(II) ions.
• This fluorescent nanomaterial holds promise for sensitive and reusable detection of toxic heavy metals in environmental monitoring.