title: A QCM-D-based biosensor for E. coli O157:H7 highlighting the relevance of the dissipation slope as a transduction signal.
abstract: A biosensor for detection of viable Escherichia coli (E. coli) O157:H7 is developed using a quartz crystal microbalance with dissipation monitoring (QCM-D). The detection platform is based on the immobilization of affinity purified polyclonal antibodies onto gold-coated QCM-D quartz crystals via a cysteamine self-assembled monolayer. QCM-D measurements conducted over a broad range of bacterial cell concentrations show that the optimal biosensor response is the initial slope of the dissipation shift as a function of elapsed time (D(slope)). A highly log-log linear response in the initial D(slope) is obtained for detection of E. coli O157:H7 over a wide range of cell concentrations from 3 x 10(5) to 1 x 10(9)cells/mL. The prepared biosensor also exhibits a log-log linear working range from 10(7) to 10(9)cells/mL for E. coli K12 D21, a non-pathogenic model organism and further shows satisfactory selectivity using Bacillus subtilis. To our knowledge, this is the first study demonstrating the use of the initial D(slope) as a sensor response when using QCM-D technology.
authors.affiliation: Department of Chemical Engineering, McGill University, Montreal, Quebec H3A 2B2, Canada.
authors.forename: Charles
authors.initials: C
authors.lastname: Poitras
authors.forename: Nathalie
authors.initials: N
authors.lastname: Tufenkji
mesh_terms: D000465:Algorithms; D015374:Biosensing Techniques / Q000295:instrumentation*; D015169:Colony Count, Microbial / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D019453:Escherichia coli O157 / Q000302:isolation & purification*; D007118:Immunoassay / Q000295:instrumentation*; D055617:Micro-Electrical-Mechanical Systems / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity