Colorimetric-Fluorescent-Magnetic Nanosphere-Based Multimodal Assay Platform for Salmonella Detection

Area of Science:

• Food Safety
• Analytical Chemistry
• Biotechnology

Background:

• Rapid and sensitive detection of foodborne pathogens is crucial for timely diagnosis and public health.
• Current methods for pathogen detection can be time-consuming and lack sensitivity for practical applications.

Purpose of the Study:

• To develop a multisignal readout lateral flow immunoassay (LFIA) for the sensitive and rapid detection of Salmonella typhimurium (S. typhi).
• To utilize novel colorimetric-fluorescent-magnetic nanospheres (CFMNs) for enhanced pathogen separation, enrichment, and detection.

Main Methods:

• Development of an LFIA utilizing CFMNs as labels for S. typhi detection.
• Integration of magnetic separation for enhanced anti-interference and sensitivity.
• Multisignal readout (colorimetric, fluorescent, magnetic) for quantitative analysis.

Main Results:

• Naked eye detection limit of 1.88 × 10^4 CFU/mL S. typhi.
• Detection limit of 3.75 × 10^3 CFU/mL S. typhi using a magnetic assay reader, significantly lower than other label-based LFIAs.
• Quantitation range of 1.88 × 10^4 to 1.88 × 10^7 CFU/mL based on fluorescence and magnetic signals.
• Successful detection of S. typhi in complex matrices including tap water, milk, fetal bovine serum, and whole blood.

Conclusions:

• The developed multisignal LFIA with CFMNs offers a highly sensitive and rapid method for S. typhi detection.
• The assay's ability to perform in complex matrices highlights its potential for real-world food safety and clinical diagnostics.
• Magnetic separation significantly improves the assay's performance and practical applicability.