Measuring the induced membrane voltage with Di-8-ANEPPS.
Placement of a cell into an external electric field causes a local charge redistribution inside and outside of the cell in the vicinity of the cell membrane, resulting in a voltage across the membrane. This voltage, termed the induced membrane voltage (also induced transmembrane voltage, or induced transmembrane potential difference) and denoted by DeltaPhi, exists only as long as the external field is present. If the resting voltage is present on the membrane, the induced voltage superimposes (adds) onto it. By using one of the potentiometric fluorescent dyes, such as di-8-ANEPPS, it is possible to observe the variations of DeltaPhi on the cell membrane and to measure its value noninvasively. di-8-ANEPPS becomes strongly fluorescent when bound to the lipid bilayer of the cell membrane, with the change of the fluorescence intensity proportional to the change of DeltaPhi. This video shows the protocol for measuring DeltaPhi using di-8-ANEPPS and also demonstrates the influence of cell shape on the amplitude and spatial distribution of DeltaPhi.
Pucihar
Gorazd
G
Department of Biomedical Engineering, Faculty of Electrical Engineering, University of Ljubljana. gorazd.pucihar@fe.uni-lj.si
Kotnik
Tadej
T
Miklavcic
Damijan
D
D000818:Animals; D016466:CHO Cells; D002462:Cell Membrane / Q000378:metabolism / Q000502:physiology*; D006224:Cricetinae; D003412:Cricetulus; D005456:Fluorescent Dyes / Q000737:chemistry* / Q000378:metabolism; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D008564:Membrane Potentials / Q000502:physiology; D011199:Potentiometry / Q000379:methods*; D011726:Pyridinium Compounds / Q000737:chemistry* / Q000378:metabolism
C089669:1-(3-sulfonatopropyl)-4-(beta-(2-(di-n-octylamino)-6-naphthyl)vinyl)pyridinium betaine; D005456:Fluorescent Dyes; D008051:Lipid Bilayers; D011726:Pyridinium Compounds