title: Microfluidic electrochemical assay for rapid detection and quantification of Escherichia coli.
abstract: Microfluidic electrochemical biosensor for performing Loop-mediated isothermal amplification (LAMP) was developed for the detection and quantification of Escherichia coli. The electrochemical detection for detecting the DNA amplification was achieved using Hoechst 33258 redox molecule and linear sweep voltametry (LSV). The DNA aggregation and minor groove binding with redox molecule cause a significant drop in the anodic oxidation of LSV. Unlike other electrochemical techniques, this method does not require the probe immobilization and the detection of the bacteria can be accomplished in a single chamber without DNA extraction and purification steps. The isothermal amplification time has a major role in the quantification of the bacteria. We have shown that we could detect and quantify 24 CFU/ml of bacteria and 8.6 fg/μl DNA in 60 min and 48 CFU/ml of bacteria in 35 min in LB media and urine samples. We believe that this microfluidic chip has great potential to be used as a point of care diagnostic (POC) device in the clinical/hospital application.
authors.affiliation: Institut national de la recherche scientifique, Énergie, Matériaux et Télécommunications (INRS-EMT), Université du Québec, 1650 Boul. Lionel Boulet, Varennes, Québec J3X 1S2, Canada.
authors.forename: Mohammadali
authors.initials: M
authors.lastname: Safavieh
authors.forename: Minhaz Uddin
authors.initials: MU
authors.lastname: Ahmed
authors.forename: Mona
authors.initials: M
authors.lastname: Tolba
authors.forename: Mohammed
authors.initials: M
authors.lastname: Zourob
mesh_terms: D058491:Bacterial Load / Q000295:instrumentation*; D015374:Biosensing Techniques / Q000295:instrumentation*; D003217:Conductometry / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D004926:Escherichia coli / Q000302:isolation & purification*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity