Electronics: Getting Under Your Skin

In General Electric’s Space Sciences Laboratory at Valley Forge, Pa., they are wiring rats to radios that draw all their electrical power from the bodies of the rodents themselves.

The faint electrical currents generated by living tissues, says G. E. Biologist John J. Konikoff, are nothing new. They have been used for many years in instruments, such as electrocardiographs, to show the condition of the body, but the currents were too weak to consider as serious power sources. Now transistors and other miniature electronic devices, which use only infinitesimal amounts of current, have changed all that.

Working in Konikoffs laboratory, L. W. Reynolds implants corrosion-resistant electrodes in his rats, one of them just under the belly skin, the other in the abdominal cavity. Thin insulated wires lead out of the skin, and through them flows a current strong enough (155 microwatts) to run a miniature 500-kilocycle transmitter. The transmitter used at present is too big to put completely inside a rat, but the engineers believe that if it were reduced in size and tucked under the rat’s skin, its body-powered signal would be easily heard several hundred yards away. The electrodes do not seem to bother the rat much. They have been tolerated for six months, one-sixth of a rat’s normal lifetime, with no ill effects.

Using rabbits and dogs, Konikoff plans to put the whole works, electrodes and transmitter, inside the skin and leave the package there for long periods, the transmitter broadcasting all the time. The ultimate purpose is to develop body-powered devices for use inside humans. One possibility is the “pacemaker,” which gives electrical timing to ailing hearts. Existing pacemakers tucked into human bodies get their electricity from small batteries that must be replaced periodically by a surgical operation. This should not be necessary, says Konikoff. The body’s own electricity can keep a pacemaker running indefinitely.

Another possibility is an internal telemetering system to report vital information such as heart beat, blood pressure, brain waves, etc. A man with such a device healed inside his skin would need to trail no wires. His physical condition could be checked from a distance without his knowing that a doctor was listening to his insides.