Smartphone-Based Fluorescence/Colorimetric Dual-Mode Aptasensor for the Detection of Salmonella Using Multivalent...

Area of Science:

• Biotechnology
• Biosensing
• Food Safety

Background:

• Foodborne illnesses caused by Salmonella pose significant public health risks.
• Rapid and sensitive detection methods for Salmonella are crucial for food safety and clinical diagnostics.

Purpose of the Study:

• To develop a dual-mode aptasensor for rapid and sensitive detection of Salmonella.
• To integrate the aptasensor with a smartphone for portable analysis.
• To enhance detection sensitivity and specificity using aptamers and catalytic hairpin assembly.

Main Methods:

• Construction of a dual-mode fluorescent/colorimetric aptasensor using multivalent aptamer competitive assays and catalytic hairpin assembly (CHA).
• Design of a tetrahedral DNA nanostructure-based multivalent aptamer probe for signal amplification.
• Integration with a smartphone-based portable device for data acquisition and analysis.

Main Results:

• The aptasensor achieved quantitative detection of Salmonella in a linear range of 10 to 10^7 CFU/mL.
• Detection limits were as low as 28 CFU/mL (colorimetric) and 10 CFU/mL (fluorescent).
• High specificity was demonstrated in various food samples (milk, egg, cod, chicken).

Conclusions:

• The developed aptasensor provides a rapid, sensitive, and specific method for Salmonella detection.
• The smartphone integration enables portable and on-site food safety monitoring and clinical diagnostics.
• The platform's versatility allows for potential detection of other bacterial pathogens.