A Bacteriophage Protein-Based Impedimetric Electrochemical Biosensor for the Detection of Campylobacter jejuni

<i>Campylobacter jejuni</i> is a common foodborne pathogen found in poultry that can cause severe life-threatening illnesses in humans. It is important to detect this pathogen in food to manage foodborne outbreaks. This study reports a novel impedimetric phage protein-based biosensor to detect <i>C. jejuni</i> NCTC 11168 at 100 CFU/mL concentrations using a genetically engineered receptor-binding phage protein, FlaGrab, as a bioreceptor. The electrochemical impedance spectroscopy (EIS) technique was employed to measure changes in resistance upon interaction with <i>C. jejuni</i>. The sensitivity of the phage protein-immobilized electrode was assessed using the various concentrations of <i>C. jejuni</i> NCTC 11168 ranging from 10²-10⁹ colony forming units (CFU)/mL). The change transfer resistance of the biosensor increased with increasing numbers of <i>C. jejuni</i> NCTC 11168 cells. The detection limit was determined to be approximately 10³ CFU/mL in the buffer and 10² CFU/mL in the ex vivo samples. <i>Salmonella enterica</i> subsp. <i>enterica</i> serotype Typhimurium-291RH and <i>Listeria monocytogenes</i> Scott A were used as nontarget bacterial cells to assess the specificity of the developed biosensor. Results showed that the developed biosensor was highly specific toward the target <i>C. jejuni</i> NCTC 11168, as no signal was observed for the nontarget bacterial cells.