title: Fast and sensitive detection of foodborne pathogen using electrochemical impedance analysis, urease catalysis and microfluidics.
abstract: Early screening of pathogenic bacteria is a key to prevent and control of foodborne diseases. In this study, we developed a fast and sensitive bacteria detection method integrating electrochemical impedance analysis, urease catalysis with microfluidics and using Listeria as model. The Listeria cells, the anti-Listeria monoclonal antibodies modified magnetic nanoparticles (MNPs), and the anti-Listeria polyclonal antibodies and urease modified gold nanoparticles (AuNPs) were incubated in a fluidic separation chip with active mixing to form the MNP-Listeria-AuNP-urease sandwich complexes. The complexes were captured in the separation chip by applying a high gradient magnetic field, and the urea was injected to resuspend the complexes and hydrolyzed under the catalysis of the urease on the complexes into ammonium ions and carbonate ions, which were transported into a microfluidic detection chip with an interdigitated microelectrode for impedance measurement to determine the amount of the Listeria cells. The capture efficiency of the Listeria cells in the separation chip was ∼93% with a shorter time of 30min due to the faster immuno-reaction using the active magnetic mixing. The changes on both impedance magnitude and phase angle were demonstrated to be able to detect the Listeria cells as low as 1.6×10(2)CFU/mL. The detection time was reduced from original ∼2h to current ∼1h. The recoveries of the spiked lettuce samples ranged from 82.1% to 89.6%, indicating the applicability of this proposed biosensor. This microfluidic impedance biosensor has shown the potential for online, automatic and sensitive bacteria separation and detection.
authors.affiliation: MOA Key Laboratory of Agricultural Information Acquisition Technology (Beijing), China Agricultural University, Beijing, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Chen
authors.affiliation: MOA Key Laboratory of Agricultural Information Acquisition Technology (Beijing), China Agricultural University, Beijing, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Wang
authors.affiliation: MOA Key Laboratory of Agricultural Information Acquisition Technology (Beijing), China Agricultural University, Beijing, China.
authors.forename: Gaozhe
authors.initials: G
authors.lastname: Cai
authors.affiliation: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, China.
authors.forename: Yonghua
authors.initials: Y
authors.lastname: Xiong
authors.affiliation: State Key Lab of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Science, Beijing, China.
authors.forename: Yuntao
authors.initials: Y
authors.lastname: Li
authors.affiliation: Modern Precision Agriculture System Integration Research Key Laboratory of Ministry of Education, China Agricultural University, Beijing, China.
authors.forename: Maohua
authors.initials: M
authors.lastname: Wang
authors.affiliation: Hebei Province Institute of Veterinary Drug Control, Shijiazhuang, China.
authors.forename: Huiling
authors.initials: H
authors.lastname: Huo
authors.affiliation: MOA Key Laboratory of Agricultural Information Acquisition Technology (Beijing), China Agricultural University, Beijing, China. Electronic address: jianhan@cau.edu.cn.
authors.forename: Jianhan
authors.initials: J
authors.lastname: Lin
mesh_terms: D015373:Bacterial Typing Techniques / Q000295:instrumentation; D002384:Catalysis; D058266:Dielectric Spectroscopy / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005504:Food Analysis / Q000295:instrumentation*; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology / Q000295:instrumentation; D007118:Immunoassay / Q000295:instrumentation; D056656:Lab-On-A-Chip Devices; D008087:Listeria / Q000276:immunology / Q000302:isolation & purification*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014510:Urease / Q000737:chemistry / Q000276:immunology*
chemical_list: D014510:Urease
keywords: Immunomagnetic separation; Listeria monocytogenes; Microfluidic impedance biosensor; Phase angle; Urease catalysis