title: Alternating Current-Dielectrophoresis Collection and Chaining of Phytoplankton on Chip: Comparison of Individual Species and Artificial Communities.
abstract: The capability of alternating current (AC) dielectrophoresis (DEP) for on-chip capture and chaining of the three species representative of freshwater phytoplankton was evaluated. The effects of the AC field intensity, frequency and duration on the chaining efficiency and chain lengths of green algaChlamydomonas reinhardtii, cyanobacteriumSynechocystissp. and diatomCyclotella meneghinianawere characterized systematically.C. reinhardtiishowed an increase of the chaining efficiency from 100 Hz to 500 kHz at all field intensities;C. meneghinianapresented a decrease of chaining efficiency from 100 Hz to 1 kHz followed by a significant increase from 1 kHz to 500 kHz, whileSynechocystissp. exhibited low chaining tendency at all frequencies and all field intensities. The experimentally-determined DEP response and cell alignment of each microorganism were in agreement with their effective polarizability. Mixtures of cells in equal proportion or 10-times excess ofSynechocystissp. showed important differences in terms of chaining efficiency and length of the chains compared with the results obtained when the cells were alone in suspension. While a constant degree of chaining was observed with the mixture ofC. reinhardtiiandC. meneghiniana, the presence ofSynechocystissp. in each mixture suppressed the formation of chains for the two other phytoplankton species. All of these results prove the potential of DEP to discriminate different phytoplankton species depending on their effective polarizability and to enable their manipulation, such as specific collection or separation in freshwater.
authors.affiliation: Environmental Biogeochemistry and Ecotoxicology, Department F.-A. Forel for Environmental and Aquatic Sciences, Earth and Environmental Science, Faculty of Sciences, University of Geneva, 66 Boulevard Carl-Vogt, CH-1211 Genève 4, Switzerland. coralie.suscillon@unige.ch.
authors.forename: Coralie
authors.initials: C
authors.lastname: Siebman
authors.affiliation: Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695-7905, USA. odvelev@ncsu.edu.
authors.forename: Orlin D
authors.initials: OD
authors.lastname: Velev
authors.affiliation: Environmental Biogeochemistry and Ecotoxicology, Department F.-A. Forel for Environmental and Aquatic Sciences, Earth and Environmental Science, Faculty of Sciences, University of Geneva, 66 Boulevard Carl-Vogt, CH-1211 Genève 4, Switzerland. vera.slaveykova@unige.ch.
authors.forename: Vera I
authors.initials: VI
authors.lastname: Slaveykova
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D016764:Cell Polarity; D016825:Chlamydomonas reinhardtii / Q000502:physiology; D017377:Diatoms / Q000502:physiology*; D005618:Fresh Water / Q000382:microbiology; D056656:Lab-On-A-Chip Devices / Q000382:microbiology*; D010839:Phytoplankton / Q000502:physiology*; D046939:Synechocystis / Q000502:physiology; D060753:Water Quality
keywords: AC dielectrophoresis; chaining efficiency; cyanobacteria; diatom; freshwater; green algae; phytoplankton