A single‐walled carbon nanotubes‐based electrochemical impedance immunosensor for on‐site detection of Listeria monocytogenes

• Published in: Journal of food science 2022-01, Vol.87 (1), p.280-288
• Main Authors: Lee, Bog Eum, Kang, Taiyoung, Jenkins, Daniel, Li, Yong, Wall, Marisa M., Jun, Soojin
• Format: Article
• Language: English
• Subjects: Antibodies; Biosensing Techniques; biosensor; Biosensors; Bovine serum albumin; Carbon; E coli; EIS; Electric Impedance; Electrochemistry; Electron transfer; Food; Food Microbiology; food pathogens; Food safety; Immunoassay; Immunosensors; Impedance; Listeria; Listeria monocytogenes; Molecular interactions; Nanotechnology; Nanotubes; Nanotubes, Carbon; Polyethyleneimine; portable; Potentiostats; Salmonella; Selectivity; Sensors; Serum albumin; Single wall carbon nanotubes; Smartphones; Streptavidin; SWCNT
• ISSN: 0022-1147; 1750-3841
• DOI: 10.1111/1750-3841.15996

Real‐time and sensitive detection of pathogenic bacteria in food is in high demand to ensure food safety. In this study, a single‐walled carbon nanotubes (SWCNTs)‐based electrochemical impedance immunosensor for on‐site detection of Listeria monocytogenes (L. monocytogenes) was developed. A gold‐plated wire was functionalized using polyethylenimine (PEI), SWCNTs, streptavidin, biotinylated L. monocytogenes antibodies, and bovine serum albumin (BSA). A linear relationship (R2 = 0.982) between the electron transfer resistance measurements and concentrations of L. monocytogenes within the range of 103–108 CFU/ml was observed. In addition, the sensor demonstrated high selectivity towards the target in the presence of other bacterial cells such as Salmonella Typhimurium and Escherichia coli O157:H7. To facilitate the demand for on‐site detection, the sensor was integrated into a smartphone‐controlled biosensor platform, consisting of a compact potentiostat device and a smartphone. The signals from the proposed platform were compared with a conventional potentiostat using the immunosensor interacted with L. monocytogenes (103–105 CFU/ml). The signals obtained with both instruments showed high consistency. Recovery percentages of lettuce homogenate spiked with 103, 104, and 105 CFU/ml of L. monocytogenes obtained with the portable platform were 90.21, 90.44, and 93.69, respectively. The presented on‐site applicable SWCNT‐based immunosensor platform was shown to have a high potential to be used in field settings for food and agricultural applications. Practical Application The developed immunosensor was developed for on‐site detection of L. monocytogenes. The limit of detection of the sensor was 103 CFU/ml with a detection time of 10 min. In order to facilitate the requirements for effective on‐site screening for food safety, the sensor was integrated into a smartphone‐controlled platform, so that the bio‐molecular interactions were converted into impedance signals and transmitted wirelessly to a smartphone by a hand‐held EIS transducer.