Controlled molecular architectures in microfluidic immunosensors for detecting Staphylococcus aureus

Area of Science:

• Biosensing
• Electrochemistry
• Food Safety

Background:

• Pathogen detection is crucial for food safety and disease diagnosis.
• Current methods are often expensive and complex.
• Staphylococcus aureus (S. aureus) is a significant pathogen in food and clinical settings.

Purpose of the Study:

• To develop a low-cost, highly sensitive method for detecting S. aureus.
• To validate the method for milk sample analysis, including differentiating from other bacteria and mastitis detection.

Main Methods:

• Fabrication of immunosensors using microfluidic devices with interdigitated electrodes.
• Coating electrodes with layer-by-layer (LbL) films of chitosan and chondroitin sulfate.
• Immobilization of anti-S. aureus antibodies and detection via impedance spectroscopy and interactive document mapping (IDMAP).

Main Results:

• Achieved a limit of detection of 2.83 CFU mL-1 and limit of quantification of 9.42 CFU mL-1 for S. aureus.
• Successfully distinguished S. aureus in milk from pure milk and samples contaminated with Escherichia coli (E. coli) and Salmonella.
• Demonstrated sensor stability for up to 25 days with detection in minutes.

Conclusions:

• The developed impedance spectroscopy-based immunosensor provides a sensitive and selective platform for S. aureus detection.
• This technology shows significant promise for real-time monitoring in the food industry, hospitals, and bovine mastitis diagnostics.