Aptamer-Conjugated Magnetic Nanoparticles Integrated with SERS for Multiplex Salmonella Detection

Area of Science:

• Biosensing
• Nanotechnology
• Food Safety

Background:

• Salmonella is a major zoonotic pathogen threatening poultry and human health.
• Timely detection of Salmonella is crucial for ensuring food and animal safety.
• Existing detection methods may require improvement in sensitivity and speed.

Purpose of the Study:

• To develop a novel aptamer-based sensor for rapid and sensitive detection of Salmonella.
• To utilize magnetic beads and core-shell nanoparticles for enhanced sensing capabilities.
• To validate the sensor's performance in detecting various Salmonella serotypes and in real food samples.

Main Methods:

• Conjugation of aptamers to Fe3O4 magnetic beads via biotin-streptavidin interaction.
• Integration of Ag@Au core-shell nanoparticles functionalized with complementary aptamers.
• Utilizing Surface-Enhanced Raman Scattering (SERS) for signal detection based on bacterial binding.
• Testing the sensor with different concentrations of Salmonella serotypes and spiked authentic samples.

Main Results:

• The aptamer sensor demonstrated a significant decrease in SERS signal upon binding with Salmonella.
• A linear relationship was observed between Salmonella concentration (10^2-10^8 CFU/mL) and the SERS signal.
• The limit of detection (LOD) was determined to be 35.51 CFU/mL.
• Recoveries in spiked authentic samples ranged from 94.0% to 100.4%, indicating high accuracy.

Conclusions:

• The developed SERS aptasensor is highly effective for detecting Salmonella.
• The sensor offers high sensitivity, specificity, and reliability for food safety applications.
• This method provides a promising tool for the timely identification of Salmonella in food products.