Agilepulse™ Id Tutorial; Delivery Into Cells Using Electroporation; General Electroporation Discussion; Figure 22: Electroporation - BTX AgilePulse ID User Manual

AgilePulse ™ ID Tutorial
Delivery Into Cells Using
Gene
Electroporation Ions

General Electroporation Discussion

Electroporation is the use of a transmembrane electric field pulse
to induce microscopic pathways (pores) in a bio-membrane. Their
Cell
presence allows molecules, ions, and water to pass from one
Membrane
side of the membrane to the other. As the right side bar shows,
Before Field Applied
when the electric field is applied, the ions inside and outside the
cell membrane migrate. As the charge builds up on either side of
the membrane, the membrane weakens and the pathways form
permitting material outside of the cell to enter. If the electric
field is promptly removed the pathways close and the membrane
reseals. If the electric field duration is too long the pathways
increase and the cell is killed. Efficient electroporation depends on
proper selection of electric field waveforms. The electropores are
located primarily on the membrane areas which are closest to the
electrodes. The pathways form in about a microsecond and seal
in seconds to minutes. The duration of the electric field is tens of Field Applied-Ions Move
microseconds to tens of milliseconds.
The use of electroporation was described by Neumann in the early
1980s. The routine use of electroporation became very popular
with researchers through the 1980s because it was found to be a
practical way to place drugs, or other molecules into cells. In the
late 1980s, scientists began to use electroporation for applications
in multi-cellular tissue.
In the early 1990s Lluis Mir of the Institute Gustave-Roussy was
the first to use electroporation in a human trial to treat external
Field Applied-Pathways Form
tumors.
Research has shown that the induction of pathways is affected by
three major factors. First, cell-to-cell biological variability causes
some cells to be more sensitive to electroporation than other
cells. Second, for pathways to be induced, the product of the
pulse amplitude and the pulse duration has to be above a lower
limit threshold. Third, the number of pathways and effective
pathway diameter increases with the product of "amplitude" and
"duration." Although other factors are involved, this threshold
is now understood to be largely dependent on a fourth factor,
Field Removed-Membrane Seals
the reciprocal of cell size. If the upper limit threshold is reached
pore diameter and total pore area are too large for the cell to

Figure 22: Electroporation

repair by any spontaneous or biological process. The result is
irreversible damage to the cell or cell lysis. Because the mechanism
of electroporation is not well understood, the development of
protocols for a particular application has usually been achieved
empirically, by adjusting pulse parameters (amplitude, duration,
number and inter-pulse interval).
AgilePulse ID In Vivo Gene Delivery System
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Publication 015-101444 Rev 2.0 • www.btxonline.com