Nature Vol. 248 April 5 1974, p475 ( News and Views )

Semiconductors in the human body?

from our Solid State Physics Correspondent

.....Now at least one biological material has been shown to have a strikingly large conductivity when correctly excited. McGinness, Corry and Proctor, of the University of Texas Cancer Center, Houston, report in Science (183, 853; 1974) that melanins can be made to 'switch' from a poorly conducting to a highly conducting state at fairly low electric fields (say from 10K ohm- cm to 100 ohm-cm at a field of 300 V cm-1). This remarkable phenomenon occurs both in melanin made synthetically from tyrosine and in that extracted from a human melanoma. The large conduction is not destructive in any way and is reversible;. According to some tests, conduction seems to be electronic rather than ionic........

Nobel Prize in Chemistry, 2000: "for the discovery and development of conductive polymers"

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