Magnetic Nanoparticle-Assisted Cleavage-Based Detection of Foodborne Pathogens Using Nuclease-Responsive DNA Probes.

Area of Science:

• Biotechnology
• Molecular Diagnostics
• Biosensing

Background:

• Current bacterial detection methods often lack speed and sensitivity.
• Need for rapid, specific detection of viable bacteria in food and environmental samples.

Purpose of the Study:

• To develop an ultrarapid and sensitive bacterial detection platform.
• To integrate nuclease-responsive DNA probes with magnetic separation for enhanced specificity and reduced background noise.

Main Methods:

• Utilized dual-labeled DNA probes (3'-biotin, 5'-reporter) cleaved by bacterial nucleases.
• Employed streptavidin-conjugated magnetic nanoparticles for efficient separation of cleaved fragments.
• Integrated lysis, cleavage, separation, and readout into a workflow completed within 3 minutes.

Main Results:

• Achieved low detection limits for *Escherichia coli* (below 10 CFU/reaction with fluorescence/chemiluminescence, 10^2 CFU/reaction with colorimetric).
• Demonstrated selective detection of viable bacteria.
• Successfully identified simulated bacterial contamination in food samples using a point-of-care testing (POCT) device.

Conclusions:

• The nuclease-responsive DNA probe platform offers a practical and rapid solution for microbial surveillance.
• The integrated magnetic separation enhances assay sensitivity and specificity.
• The developed POCT device shows real-world applicability for frontline food and environmental safety testing.