Au@mSiO₂ core-shell nanoparticles loaded with fluorescent dyes: synthesis and application for imaging performance

Area of Science:

• Materials Science
• Nanotechnology
• Chemistry

Background:

• Core-shell nanoparticles offer unique properties for various applications.
• Surface modification is crucial for controlling nanoparticle functionality.
• Mesoporous silica offers a versatile platform for material integration.

Purpose of the Study:

• To synthesize Au@mSiO2 core-shell nanoparticles with tunable surface charges.
• To investigate the efficient loading of negatively charged dyes onto these nanoparticles.
• To evaluate the suitability of these functionalized nanoparticles for dual-mode imaging.

Main Methods:

• One-pot synthesis of Au@mSiO2 core-shell nanoparticles.
• Surface modification with positively charged alkyl chains of varying lengths.
• Loading of heterogeneous negatively charged dyes through electrostatic adsorption.
• Characterization using fluorescence spectroscopy and transmission electron microscopy (TEM).

Main Results:

• Successfully synthesized Au@mSiO2 core-shell nanoparticles with controlled surface potentials.
• Demonstrated efficient dye loading due to strong electrostatic interactions.
• Observed that dyes were confined to the nanoparticle surface, preventing tunneling.
• Maintained high fluorescence intensity post-dye loading.
• Achieved dual-mode imaging capability (TEM and fluorescence).

Conclusions:

• The developed one-pot method provides a facile route to functionalized Au@mSiO2 nanoparticles.
• Electrostatic adsorption is an effective strategy for loading dyes onto these nanoparticles.
• The surface confinement of dyes is beneficial for future studies on nanoparticle loading and release.
• The resulting nanoparticles are suitable for dual-mode microscopic imaging.