title: Magnetically-assisted impedimetric detection of bacteria using phage-modified carbon microarrays.
abstract: This study presents an investigation on the possibility of improving the detection limit of bacteria with an inexpensive electrochemical, impedimetric sensor platform, by integrating the sensor with magnetic manipulation. The approach uses T4 bacteriophage coated Dynabeads to selectively capture and concentrate E. coli K12 cells from samples, to increase the sensitivity of detection at the surface of functionalized screen-printed carbon microarrays. Fluorescence and flow cytometry measurements indicate that the surface modification of the magnetic beads, with phages, and binding with the bacteria, were successful. Integration of the screen-printed carbon-based impedimetric sensor, with a magnetic manipulation system, was found to improve the sensitivity of the device, decreasing the limit of detection of E. coli K12 from 10(4) to 10(3) cfu/mL. We have also demonstrated that this approach provides for more specific detection of bacteria, enabling the operator to account for non-specific adsorption, and detection of bacteria in more complex (real) samples (milk).
authors.affiliation: Biophage Pharma, 6100 Royalmount, Montreal (QC), Canada H4P 2R2; Department of Chemistry and Biochemistry, Concordia University, 7141 Sherbrooke W., Montreal (QC), Canada H4B 1R6.
authors.forename: Arghavan
authors.initials: A
authors.lastname: Shabani
authors.forename: Christophe A
authors.initials: CA
authors.lastname: Marquette
authors.forename: Rosemonde
authors.initials: R
authors.lastname: Mandeville
authors.forename: Marcus F
authors.initials: MF
authors.lastname: Lawrence
mesh_terms: D000818:Animals; D017122:Bacteriophage T4 / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation*; D002244:Carbon / Q000737:chemistry*; D015169:Colony Count, Microbial; D017097:Electric Impedance; D055664:Electrochemical Techniques; D048168:Escherichia coli K12 / Q000302:isolation & purification*; D005506:Food Contamination / Q000032:analysis*; D057230:Limit of Detection; D059346:Magnets; D008892:Milk / Q000382:microbiology; D011327:Printing
chemical_list: D002244:Carbon
keywords: Bacteria; E. coli; EIS; Electrode; Impedimetric; Magnetic separation; Phage