Exercise 6.7 - Electrical Properties of Artificial Membranes
- Artificial lipid membrane from Exercise 6.6
- KCl electrodes 6
- DC voltage source
- Wheatstone bridge to monitor resistance 7
- Insert a salt bridge connected to standard electrodes and
suitable for measuring both resistance and potential differences
across the membrane.
- Measure the resistance of the synthetic membrane by passing
a small DC current through the membrane and measuring the drop in
If one knows the applied voltage (100-200 mV) and the measured
voltage ( mV), the following formula will give the resistance
is the series resistance
is the calibrated input voltage
is the voltage appearing across the membrane.
- Calculate the area of the membrane based on the diameter of
the drilled hole, and multiply R
(measured resistance) by the area of the membrane. This will give
a normalized resistance in ohms-cm.
- Compare your calculated value to the data in Table 6.4.
- Divide your calculated value by the thickness of the
to yield the membrane resistivity or specific resistance.
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Cell Biology Laboratory Manual
Dr. William H. Heidcamp, Biology Department, Gustavus Adolphus College,
St. Peter, MN 56082 -- firstname.lastname@example.org