Fast analysis of Staphylococcus aureus in food products using disposable label-free nano-electrochemical immunosensor chips

Rapid analysis and early detection of food poisoning has become an important factor for the recognition and prevention of problems associated with food safety and public health. Accordingly, a number of different methods have been developed and applied for the detection and identification of S. aureus. However, these methods are not suitable for on-site applications as they are time-consuming and laborious. Thus, a label-free impedimetric immunosensor was constructed using the self-assembling monolayer formation of the lipoic at the AuNPs@Fe3O4-screen printed electrode. The formed layer of the lipoic acid supported the covalent immobilization of anti-S. aureus antibody as the selective bio-recognition element. As a result, a specific immune reaction between the whole pathogen cells and the immobilized antibody was monitored under optimized conditions. Electrochemical impedance spectroscopy along with other chemical assessments were used to verify the stepwise assembly of the immunosensor fabrication. Accordingly, the newly developed impedimetric immunosensor showed high sensitivity and selectivity towards the targeting bacterial strain with the limit of detection and limit of quantification of 0.10, and 0.34 CFU/mL, respectively. Eventually, the designed immunosensor was successfully implemented to analyze the S. aureus contamination in milk and meat samples, whereas the obtained results were validated.

Automated summary

Rapid analysis and early detection of food poisoning is crucial for food safety and public health. A label-free impedimetric immunosensor was developed for the detection and identification of S. aureus, which showed high sensitivity and selectivity. The immunosensor was successfully used to analyze S. aureus contamination in milk and meat samples.