title: Differentiation of Escherichia coli serotypes using DC gradient insulator dielectrophoresis.
abstract: Bacteria play a significant role in both human health and disease. An estimated 9.4 million cases of foodborne illness occur in the United States each year. As a result, rapid identification and characterization of microorganisms remains an important research objective. Despite limitations, selective culturing retains a central role among a cadre of identification strategies. For the past decade, separations-based approaches to rapid bacterial identification have been under investigation. Gradient insulator dielectrophoresis (g-iDEP) promises benefits in the form of rapid and specific separation of very similar bacteria, including serotypes of a single species. Furthermore, this approach allows simultaneous concentration of analyte, facilitating detection and downstream analysis. Differentiation of three serotypes or strains of Escherichia coli bacteria is demonstrated within a single g-iDEP microchannel, based on their characteristic electrokinetic properties. Whole cells were captured and concentrated using a range of applied potentials, which generated average electric fields between 160 and 470 V/cm. Bacteria remained viable after exposure to these fields, as determined by cellular motility. These results indicate the potential g-iDEP holds in terms of both separatory power and the possibility for diagnostic applications.
authors.affiliation: Department of Chemistry and Biochemistry, Arizona State University, Tempe, 85287-1604, AZ, USA.
authors.forename: Paul V
authors.initials: PV
authors.lastname: Jones
authors.forename: Alexa F
authors.initials: AF
authors.lastname: DeMichele
authors.forename: LaKeta
authors.initials: L
authors.lastname: Kemp
authors.forename: Mark A
authors.initials: MA
authors.lastname: Hayes
mesh_terms: D004553:Electric Conductivity; D004560:Electricity; D004586:Electrophoresis / Q000295:instrumentation* / Q000379:methods; D004926:Escherichia coli / Q000302:isolation & purification*; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D009068:Movement; D012703:Serotyping / Q000295:instrumentation / Q000379:methods*