Impedance microbiology-on-a-chip: Microfluidic bioprocessor for rapid detection of bacterial metabolism

Rafael Gómez-Sjöberg, Dallas T. Morisette, Rashid Bashir

Research output: Contribution to journalArticlepeer-review


Detection of a few live bacterial cells in many industrial or clinical samples is a very important technological problem. We have developed a microscale technique for concentrating bacterial cells from a dilute sample, by factors on the order of 104 to 105, and detecting their metabolic activity by purely electrical means. The technique was implemented on a silicon-based microfluidic chip where the cells are concentrated and incubated in a chamber with a volume of 400 pL. Concentration and capture are obtained by the use of dielectrophoresis on the bacterial cells, and metabolism detection is achieved by means of impedance measurements of the medium in which the bacteria are incubated. Performing impedance-based detection at the microscale results in drastically reduced detection times for dilute bacterial samples, thanks to the ability to efficiently concentrate and capture the cells in an extremely small volume. Such concentration eliminates the need to amplify the bacterial population by long culture steps. This detection technique can be used for a wide variety of applications.

Original languageEnglish (US)
Pages (from-to)829-838
Number of pages10
JournalJournal of Microelectromechanical Systems
Issue number4
StatePublished - Aug 2005
Externally publishedYes


  • Bacterial detection
  • Bacterial metabolism
  • Biochip
  • Impedance microbiology

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Mechanical Engineering


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