|LEE, BOG EUM - University Of Hawaii|
|KANG, TAIYONG - University Of Hawaii|
|JENKINS, DANIEL - University Of Hawaii|
|LI, YONG - University Of Hawaii|
|JUN, SOOJIN - University Of Hawaii|
Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/1/2021
Publication Date: 12/21/2021
Citation: Lee, B., Kang, T., Jenkins, D.M., Li, Y., Wall, M.M., Jun, S. 2021. A single-walled carbon nanotubes-based electrochemical impedance immunosensor for on-site detection of Listeria monocytogenes. Journal of Food Science. 87(1):280-288. https://doi.org/10.1111/1750-3841.15996.
Interpretive Summary: Real-time and sensitive detection of pathogenic bacteria in food is in high demand to ensure food safety. In this study, an electrochemical impedence immunosensor was developed for on-site detection of Listeria monocytogenes. The limit of detection of the sensor was 10^3 colony forming units (CFU)/mL with a detection time of 10 minutes. The sensor was integrated into a smartphone-controlled platform to facilitate the requirements for effective on-site screening for food safety. The bio-molecular interactions were converted into impedance signals and transmitted wirelessly to a smartphone by a hand-held EIS transducer.
Technical Abstract: 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 tungsten wire was functionalized by coating with polyethylenimine, SWCNTs, streptavidin, biotinylated L.monocytogenes antibodies, and bovine serum albumin. A linear relationship (R2 = 0.982) between the electron transfer resistance measurements and concentrations of L. monocytogenes within the range of 10^3 - 10^8 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 (10^3 - 10^5 CFU/mL). The signals obtained with both instruments showed high consistency. Recovery percentages of lettuce homogenate spiked with 10^3, 10^4, and 10^5 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.