Investigating the Use of Impedance Flow Cytometry for Classifying the Viability State of E. coli

Christian Vinther Bertelsen*, Julio César Franco, Gustav Erik Skands, Maria Dimaki, Winnie Edith Svendsen

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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Bacteria detection, counting and analysis is of great importance in several fields. When viability plays a major role in decision making, the counting of colony-forming units grown on agar plates remains the gold standard. However, because plate counts depend on the growth of the bacteria, it is a slow procedure and only works with culturable species. Impedance flow cytometry (IFC) is a promising technology for particle detection, counting and characterization. It relies on the perturbation of an electric field by particles flowing through a microfluidic channel. The perturbation is directly related to the electrical properties of the particles, and therefore provides information about their composition and structure. In this work we investigate whether IFC can be used to differentiate viable cells from inactivated cells. Our findings demonstrate that the specific viability state of the bacteria has to be considered, but that with proper characterization thresholds, IFC can be used to classify bacterial viability states. By using three different inactivation methods-ethanol, heat and autoclavation-we have been able to show that the impedance response of Escherichia coli depends on its viability state, but that the specific response depends on the inactivation method. With these findings we expect to be able to optimize IFC for more reliable bacteria detection and counting in the future.
Original languageEnglish
Article number6339
Issue number21
Number of pages16
Publication statusPublished - 2020


  • Impedance spectroscopy
  • Impedance flow cytometry
  • Bacteria detection
  • Bacteria characterization
  • Bacteria inactivation
  • Lab-on-a-chip


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