Boosting Sensitivity, Stability, and Speed: A Polydopamine-Engineered Silver Nanoparticle Lateral Flow Immunoassay
Xinge Mo1,2, Shuhong Zhang1,2, Zixuan He1,2
1State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang 330047, China.
Toxins
|March 27, 2026
Summary
New polydopamine-functionalized silver nanoparticles (Ag@PDA NPs) significantly improve lateral flow immunoassay (LFIA) sensitivity for detecting mycotoxins like aflatoxin B1. This advancement offers enhanced stability and visual contrast for more reliable food safety testing.
Area of Science:
- Nanotechnology
- Analytical Chemistry
- Food Science
Background:
- Conventional colorimetric lateral flow immunoassays (LFIAs) lack sensitivity for detecting low-molecular-weight contaminants like mycotoxins.
- Silver nanoparticles (AgNPs) offer high molar extinction coefficients but suffer from instability and poor visual contrast in LFIAs.
- Developing stable, high-performance colorimetric probes is crucial for improving LFIA detection capabilities.
Purpose of the Study:
- To engineer robust polydopamine-functionalized silver nanoparticles (Ag@PDA NPs) as advanced signal probes for LFIAs.
- To enhance the sensitivity, stability, and visual contrast of colorimetric detection in LFIAs.
- To apply the developed Ag@PDA NPs for the sensitive detection of aflatoxin B1 (AFB1) in maize.
Main Methods:
- Synthesis of polydopamine-functionalized silver nanoparticles (Ag@PDA NPs).
- Characterization of Ag@PDA NPs for stability, colorimetric contrast, and hydrophilicity.
- Development and optimization of an LFIA using Ag@PDA NPs for AFB1 detection.
- Validation of the LFIA in buffer and spiked maize samples.
Main Results:
- Ag@PDA NPs demonstrated superior long-term stability and enhanced colorimetric contrast compared to conventional probes.
- The engineered probes exhibited improved hydrophilicity, leading to faster and more uniform migration on test strips.
- The developed LFIA achieved a limit of detection (LOD) of 0.23 ng mL-1 for AFB1, a 2.17-fold improvement over gold-based LFIAs.
- High reliability was confirmed in maize samples, with recoveries between 95.70% and 119.28% and good precision.
Conclusions:
- Polydopamine functionalization effectively stabilizes silver nanoparticles, overcoming limitations for LFIA applications.
- Ag@PDA NPs serve as high-performance signal probes, significantly enhancing LFIA sensitivity and reliability.
- The developed assay provides a promising tool for sensitive and accurate mycotoxin detection in food safety testing.
