Magnetic Nanoparticles-Enhanced Biosensor for the Detection of Campylobacter spp. in Raw Poultry Products

Introduction: Rapid and accurate detection of Campylobacter spp. at low concentrations in raw poultry products is a critical challenge. One issue that affects many biosensor protocols is the nature of the interferences present in complex matrixes, which often results in loss of sensitivity and specificity.

Purpose: This study was to conducted to develop and validate a highly sensitive Surface Plasmon Resonance (SPR) sensor combining antibody-functionalized magnetic nanoparticles for rapid detection of Campylobacter in raw poultry products.

Methods: Magnetic nanoparticles, which were functionalized using monoclonal antibodies specific to Campylobacter spp. surface antigens, were used to separate Campylobacter from food matrixes. The magnetic nanoparticles used in the protocol were functioned not only as probes to selectively bind and separate Campylobacter, but also as an amplification regent to enhance the SPR signal. The sensor protocol was developed based on a sandwich format with paired monoclonal antibodies.

Results: Campylobacter was detected at concentrations as low as 100 cfu/mL and the signal showed a linear range between 1.0 × 10² and 2.4 × 10⁵ cfu/mL. The use of magnetic nanoparticles in the SPR protocol provided three orders of magnitude in the improvement of sensitivity toward Campylobacter spp. compared to the regular SPR sensor with direct detection format. The specificity of the SPR sensor was examined with a cocktail of non-target bacteria (Escherichia coli and Enterobacter cloacae). No significant signal was detected in the presence of these bacteria. Of 108 raw chicken samples inoculated with a cocktail of Campylobacter spp. at levels between 10 and 100 cfu/g, 106 samples were detected as positive.

Significance: The developed SPR sensor has potential to provide a simple, low-cost and sensitive method for detection of Campylobacter spp. in poultry products.