MIT and Harvard scientists have figured out a way to harness a tiny electric current in the inner ear.
The work, believed to be the first to pull electricity from the cochlea and use it to drive electronics, could make it possible some day to make self-powered implantable medical devices to diagnose and treat disorders of the ear or even the brain, the researchers wrote last week in the journal Nature Biotechnology.
Anantha Chandrakasan of the MIT Microsystem Technology Laboratories in Cambridge, Mass., and Konstantina Stankovich of the Massachusetts Eye and Ear Infirmary in Bostonand colleagues took advantage of the ear's own way of powering hearing -- a battery-like feature known as the endocochlear potential, which is created because of differences in the number of potassium ions (charged atoms) on either side of a membrane deep in the inner ear. The endocochlear potential helps take vibrations generated from sound waves and translates them into signals to the brain's auditory nerve. The brain then processes those signals into meaningful sounds.
To capture the electricity, the team implanted electrodes in the cochleas of anesthetized Hartley Albino guinea pigs that were attached to a miniature power-harvesting chip located outside the animals' bodies.