Microfabricated device for impedance-based detection of bacterial metabolism

Rafael Gómez, Michael R. Ladisch, Arun K. Bhunia, Rashid Bashir

Research output: Contribution to journalConference article

Abstract

We present the use of a microfabricated device for impedance-based detection of a few live bacterial cells. Impedance-based detection relies on measuring changes in the AC impedance of two electrodes immersed in a liquid were the bacteria are cultured, caused by the release of ionic species by metabolizing bacterial cells. Rapid detection of a few cells (1 to 10) is possible if the cells are confined into a volume on the order or nanoliters. A microfluidic biochip prototype has been fabricated to test this miniaturized assay. The conductance of the bacterial suspensions is extracted from measuring their complex impedance in a 5.27 nl chamber in the biochip, at several frequencies between 100 Hz and 1 MHz. Measurements on suspensions of the bacteria Listeria innocua. Listeria monocytogenes, and Escherichia coli in a low conductivity buffer demonstrate that, under the current experimental conditions, the minimum detection level is between 50 and 200 live cells, after two hours of off-chip incubation. Work is in progress to develop techniques for selective capture of bacteria inside the chip, and to minimize background changes in impedance during on-chip incubation.

Original languageEnglish (US)
Pages (from-to)161-166
Number of pages6
JournalMaterials Research Society Symposium - Proceedings
Volume729
DOIs
StatePublished - Jan 1 2002
Externally publishedYes
EventBioMEMS and Bionanotechnology - San Francisco, CA, United States
Duration: Apr 1 2002Apr 3 2002

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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