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In the
past, the ECIS instrumentation has been used exclusively to monitor the
activities of living cells using electric fields too weak to be detected by
the cells. We now offer a new module, fully integrated into the normal ECIS
instrument and designed to electrically alter the cells.
The Elevated-Field Applications Module is directly incorporated into the
ECIS Model 1600R case. When called up by the software, the electronics
automatically applies an elevated current pulse to the cell covered
electrode. Depending upon the parameters selected by the user, these high
fields can be used to electroporate or wound the cells. These invasive
actions are only directed at the small population of cells in contact with
the active ECIS electrode, and once these incursions are completed, the
system returns to its normal mode to follow the fate of the altered cells.
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MDCK
cells were grown to confluence and electrically wounded using the Elevated
Field Module with the ECIS system. This micrograph shows the electrode 20
hours after healing; note the radial pattern in the cell population about
the electrode resulting from the inward cell migration. |
Electroporation
We have recently evaluated the conditions required for electroporation of
small molecules*, and beta testing is now underway to assess ECIS
electroporation using DNA constructs.
Wound
healing
The ECIS wound healing assay (Patent pending) is a novel way to replace
traditional wound-healing / migration measurements. Instead of disrupting
the cell layer mechanically and following the migration of cells to "heal"
the wound with a microscope, we employ electrical signals to both wound and
then monitor the healing process. This can be accomplished without opening
the door of the incubator and provides quantitative migration data in real
time. |
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In the figure, BSC cells were grown to
confluence in four ECIS wells before data was collected. At the point
indicated, a potential of a few volts was applied for several seconds
killing the cells and dropping the impedance to that of a cell-free
electrode (the two control wells did not receive the high field). During the
next few hours, neighbouring cells migrate into the wounded area (250 µm
diameter) replacing their dead cohorts, and the electrodes return to
impedance values of the controls. Experiments have been conducted showing
that the healing rate is strongly dependent upon cell type, medium
composition, and the protein adsorbed to the substrate. |
