THE SEMICONDUCTIVE PROPERTIES OF LIPIDS AND THEIR RELATION TO THE ELECTRICAL CONDUCTIVITY OF LIPID BILAYERS.
MICHIGAN STATE UNIV EAST LANSING DEPT OF BIOPHYSICS
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A study was made showing that lipid films in the dry state behave as electrical semiconductors with high activation energies. For phospholipids, these activation energies range from 4.8 to 6.3 e.v. Upon hydration, the activation energies decrease whereas the conductivities increase. An effect parallel to that of water is found with exposure of lipids to iodine vapor here the activation energies range from 2.7 to 3.2 e.v. With the adsorption of either water or iodine, the dielectric constant, frequency dispersion and dissipation factor of the lipids increased over the dry state values. Lipid bilayers were found to exhibit an increase of 1000 to 100000 in their electrical conductivity with exposure of the bilayer to iodine solution. Spectroscopic evidence was obtained indicating that lipids form charge-transfer complexes with iodine. This charge transfer evidence is taken as suggestive of a possible electronic conduction mechanism, not only in the lipid films, but also in the lipid bilayers.
- Electricity and Magnetism
- Atomic and Molecular Physics and Spectroscopy
- Solid State Physics