A plasmonic biosensor array exploiting plasmon coupling between gold nanorods and spheres for domoic acid detection...

Area of Science:

• Nanotechnology
• Biosensing
• Marine Toxin Detection

Background:

• Marine toxins like domoic acid (DA) pose significant risks to human health and marine ecosystems.
• Accurate and rapid detection methods for DA are crucial for food safety and environmental monitoring.
• Existing detection methods can be time-consuming or require complex instrumentation.

Purpose of the Study:

• To develop a novel immunoassay for detecting marine toxin domoic acid (DA).
• To utilize plasmonic coupling between gold nanorods and nanospheres for enhanced detection sensitivity.
• To optimize nanorod synthesis and explore different detection strategies for DA.

Main Methods:

• Optimized synthesis of gold nanorods with controlled aspect ratio and LSPR properties.
• Bio-functionalization of gold nanorods with DA hapten and gold nanospheres with anti-DA antibody.
• Detection of DA using plasmon coupling via hyperspectral imaging or darkfield microscopy.
• Investigated effects of acidity, silver to gold ratio, CTAB concentration, and seed addition on nanorod synthesis.

Main Results:

• Achieved excellent nanorods (size variation <15%, aspect ratio 3.5-5) for LSPR range 785-867 nm.
• Developed two detection methods based on LSPR shift and particle aggregation.
• Hyperspectral imaging showed a ~55 nm LSPR blue-shift due to immunoreaction.
• Darkfield microscopy enabled clear qualitative detection of 10 µM DA (p < 0.0005) with a simpler setup.

Conclusions:

• The developed immunoassay effectively detects domoic acid using plasmonic coupling.
• The darkfield microscopy method offers a simple, rapid (~30 min), and potentially high-throughput approach for DA detection.
• This novel platform holds promise for practical applications in marine toxin monitoring.