Core-Shell Gold/Silver Nanoparticles for Localized Surface Plasmon Resonance-Based Naked-Eye Toxin Biosensing

Area of Science:

• Nanotechnology
• Biosensing
• Analytical Chemistry

Background:

• Localized surface plasmon resonance (LSPR) is a key property for biodetection.
• Developing sensitive and visually detectable biosensors is crucial for various applications.

Purpose of the Study:

• To create a homogeneous optical biosensor for detecting staphylococcal enterotoxin A (SEA) with naked-eye readout.
• To synthesize and characterize core-shell nanoparticles (NPs) for enhanced biodetection capabilities.

Main Methods:

• Synthesized two types of core-shell nanoparticles: gold nanoparticles with silver shells (Au@AgNPs) and silver nanoparticles within gold shells (Ag@AuNPs).
• Tuned the localized surface plasmon resonance (LSPR) band of NPs by controlling shell thickness and surface chemistry with anti-SEA antibodies.
• Applied NPs to detect SEA spectroscopically and visually, assessing limits of detection (LODs).

Main Results:

• Au@AgNPs and Ag@AuNPs were successfully synthesized with LSPR bands tuned to specific wavelengths.
• The biosensor achieved low limits of detection for SEA: 0.2 nM for Au@AgNPs and 0.4 nM for Ag@AuNPs.
• Ag@AuNPs exhibited a more distinct color change (orange to red) for naked-eye detection.

Conclusions:

• The developed optical biosensor effectively detects SEA with high sensitivity and visual distinguishability.
• The strategy holds significant potential for medical diagnostics and environmental monitoring, particularly in resource-limited settings.