title: Dielectrophoretic separation of bacteria using a conductivity gradient.
abstract: Dielectrophoresis, the lateral motion induced on particles by non-uniform electric fields, is a sensitive function of the electrical conductivity of the particle suspending medium. This dependence is exploited in a new technique for separating bioparticles from suspended mixtures. The bioparticles are first immobilised by positive dielectrophoresis at electrodes in a separation chamber, and the conductivity of the liquid flowing through the chamber is then gradually and continuously increased so as to produce a conductivity gradient with time. The bioparticles are released from the electrodes according to their own dielectric properties and as a function of flow rate and medium conductivity. This is demonstrated for pure suspensions and mixtures of the bacteria Bacillus subtilis, Escherichia coli and Micrococcus luteus.
authors.affiliation: Institute of Molecular and Biomolecular Electronics, University of Wales, Bangor, Gwynedd, UK. gerard@sees.bangor.ac.uk
authors.forename: G H
authors.initials: GH
authors.lastname: Markx
authors.forename: P A
authors.initials: PA
authors.lastname: Dyda
authors.forename: R
authors.initials: R
authors.lastname: Pethig
mesh_terms: D001412:Bacillus subtilis / Q000302:isolation & purification; D001419:Bacteria / Q000302:isolation & purification*; D001709:Biotechnology; D004553:Electric Conductivity; D004586:Electrophoresis / Q000295:instrumentation / Q000379:methods*; D004926:Escherichia coli / Q000302:isolation & purification; D016982:Micrococcus luteus / Q000302:isolation & purification