title: Separation of viable and non-viable yeast using dielectrophoresis.
abstract: Dielectrophoresis, the movement of particles in non-uniform AC electric fields, was used to rapidly separate viable and non-viable yeast cells with good efficiency. Known mixtures of viable and heat-treated cells of Saccharomyces cerevisiae were separated and selectively isolated using positive and negative dielectrophoretic forces generated by microelectrodes in a small chamber. Good correlations with the initial known relative compositions were obtained by direct microscopic counting of cells at the electrodes after initial dielectrophoretic separation (r = 0.995), from methylene blue staining (r = 0.992) and by optical absorption measurements (r = 0.980) of the effluent after selectively flushing out the viable and non-viable cells from the chamber. Through measurement of cell viability by staining with methylene blue and plate counts, for an initial suspension of approx. 1.4 x 10(7) cells per ml containing 60% non-viable cells, the dielectrophoretically separated non-viable fraction contained 3% viable cells and the viable fraction 8% dead cells. The separation efficiency is increased by dilution of the initial suspension or by repeat operation(s). Cell viability was not affected by the separation procedure.
authors.affiliation: Institute of Molecular and Biomolecular Electronics, University of Wales, Bangor, Gwynedd, UK.
authors.forename: G H
authors.initials: GH
authors.lastname: Markx
authors.forename: M S
authors.initials: MS
authors.lastname: Talary
authors.forename: R
authors.initials: R
authors.lastname: Pethig
mesh_terms: D004586:Electrophoresis / Q000295:instrumentation / Q000379:methods*; D008839:Microelectrodes; D008853:Microscopy / Q000295:instrumentation / Q000379:methods; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000254:growth & development / Q000302:isolation & purification*