Selective detection of viable bacteria using dielectrophoretic impedance measurement method

Junya Suehiro, Ryo Hamada, Daisuke Noutomi, Masanori Shutou, Masanori Hara

Research output: Contribution to journalArticle

180 Citations (Scopus)

Abstract

This paper describes a selective detection technique of viable bacteria based on dielectrophoresis and electrical impedance measurements. The authors have previously proposed a detection technique of biological particles called dielectrophoretic impedance measurement (DEPIM) method using positive dielectrophoretic force to capture biological cells in suspension onto an interdigitated microelectrode array. By combining antigen-antibody reaction with the DEPIM, selective detection of a particular species of bacteria was demonstrated. In this present work, the authors demonstrated another selective DEPIM method utilizing cell viability dependency of dielectrophoretic force without introducing the antigen-antibody reaction. It was found that dielectrophoresis of heat-treated Escherichia coli showed strong dependency on viability when applied field frequency was as high as 1 MHz. As a result, viable bacteria could be exclusively collected by positive dielectrophoresis and selectively detected by the DEPIM technique from a suspension also containing heat-treated nonviable cells. On the other hand, nonviable bacteria obtained by UV irradiation showed little dielectrophoresis dependency on viability. According to a theoretical analysis of the dielectrophoretic force, it is suggested that heat treatment alters the dielectric properties of treated cells. In particular, a decrease in cytoplasmic conductivity, which might be caused by heat-induced perforation of cell membrane, was expected to considerably affect dielectrophoresis characteristics. Proposed selective DEPIM method was also applied to evaluation of heat sterilization effect on a real time basis. It was experimentally proved that DEPIM could evaluate viable cell number variation with heat treatment time in a considerably shorter time than conventional microbiological method based on cell incubation.

Original languageEnglish
Pages (from-to)157-168
Number of pages12
JournalJournal of Electrostatics
Volume57
Issue number2
DOIs
Publication statusPublished - Feb 1 2003

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Biotechnology
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Electrical and Electronic Engineering

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