Figure 23: Transmembrane Voltage - BTX AgilePulse ID User Manual

AgilePulse ™
Research in the late 1980s and early 1990s showed that certain
experimental conditions and parameters of electrical pulses may
be capable of causing many more molecules to move per unit time
than simple diffusion. There is also good evidence (Sukharev et al.,
1992) that DNA movement is in the opposite direction of the arrow
in the sidebar.
An additional important consideration is when the voltage pulse is
applied to the cells and medium that the amount of current that
flows is dependent on the conductivity of the material in which
the cells are located. Some material is quite conductive and severe
heating will occur if the pulse duration is too long. Therefore long
duration fields will kill cells by destroying the membrane and
heating.
The electric field in which the cells are located is produced by two
system components. The first is the voltage waveform generator
and the second is the electrode which converts the voltage into the
electric field.
Neumann, Sowers and Jordan, 1998, pages 68-73 provides the
equation that relates the transmembrane voltage (TMV) to electric
field intensity. As the charge accumulates at the membrane, which
is a capacitance, the voltage across the membrane increases.
charge
voltage
=
capacitance
As the voltage increases from its quiescent value of a few tenths of
a volt to more than 0.5 volts, pathways begin to form. The TMV is
given by:
⁄
E r | cos a|
3
-
=
TMV
2
where:
= electric field intensity in volts/cm
E
= the cell radius in cm
r
a = angle off the center line
To produce a TMV of 1 volt across the membrane of a cell with
7 µm radius, the required electric field intensity is:
⁄
1
2
-
E =
3
-4
7 *10
19
ID Tutorial
=
950 volts / cm
AgilePulse ID In Vivo Gene Delivery System
Publication 015-101444 Rev 2.0 • www.btxonline.com

Figure 23: Transmembrane Voltage