Measurement of extracellular ion fluxes using the ion-selective selfreferencing microelectrode technique

Guillaume Luxardi, Brian Reid, Fernando Ferreira, Pauline Maillard, Min Zhao

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

Cells from animals, plants and single cells are enclosed by a barrier called the cell membrane that separates the cytoplasm from the outside. Cell layers such as epithelia also form a barrier that separates the inside from the outside or different compartments of multicellular organisms. A key feature of these barriers is the differential distribution of ions across cell membranes or cell layers. Two properties allow this distribution: 1) membranes and epithelia display selective permeability to specific ions; 2) ions are transported through pumps across cell membranes and cell layers. These properties play crucial roles in maintaining tissue physiology and act as signaling cues after damage, during repair, or under pathological condition. The ion-selective self-referencing microelectrode allows measurements of specific fluxes of ions such as calcium, potassium or sodium at single cell and tissue levels. The microelectrode contains an ionophore cocktail which is selectively permeable to a specific ion. The internal filling solution contains a set concentration of the ion of interest. The electric potential of the microelectrode is determined by the outside concentration of the ion. As the ion concentration varies, the potential of the microelectrode changes as a function of the log of the ion activity. When moved back and forth near a source or sink of the ion (i.e. in a concentration gradient due to ion flux) the microelectrode potential fluctuates at an amplitude proportional to the ion flux/gradient. The amplifier amplifies the microelectrode signal and the output is recorded on computer. The ion flux can then be calculated by Fick’s law of diffusion using the electrode potential fluctuation, the excursion of microelectrode, and other parameters such as the specific ion mobility. In this paper, we describe in detail the methodology to measure extracellular ion fluxes using the ion-selective self-referencing microelectrode and present some representative results.

Original languageEnglish (US)
Article numbere52782
JournalJournal of Visualized Experiments
Volume2015
Issue number99
DOIs
StatePublished - May 3 2015

Keywords

  • Cellular biology
  • Extracellular ion fluxes
  • In vivo measurements
  • Ion-selective
  • Issue 99
  • Microelectrode
  • Self-referencing

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Chemical Engineering(all)
  • Immunology and Microbiology(all)
  • Neuroscience(all)

Fingerprint Dive into the research topics of 'Measurement of extracellular ion fluxes using the ion-selective selfreferencing microelectrode technique'. Together they form a unique fingerprint.

  • Cite this