A team from the Massachusetts Eye and Ear Infirmary have developed a cochlea chip powered by inner ear electrical signals…

Implants currently in use are powered by extra batteries, which usually require replacement over time and can make them difficult to insert. For implants such as the cochlear implant, which are placed in delicate parts of the body, a self-powered and self-sufficient implant can bring huge advantages for both the surgical team and recipient of the treatment.

The inner ear contains negatively charged potassium ions and positively charged sodium ions on either side of a membrane, helping to convert the physical force of eardrum vibrations into the electrochemical signals transmitted to the brain. This electric charge, although low, is therefore potentially able to charge the electronic implant chip. Power-conversion circuitry is also included to help power the chip.

Team member and otologic surgeon Konstantina Stankovic, said, “We have known for 60 years that this battery exists and that it’s really important for normal hearing, but nobody has attempted to use this battery to power useful electronics.”

The implant has been tested on guinea pigs and has been shown to run without incident for up to five hours after being kick-started with a radio-wave burst. Currently the device is too invasive to run for a long period of time without tissue damage, but results so far have been promising enough to develop the device further.

Other self-powered medical devices created in recent months include a radio wave-powered heart implant and infrared light-powered retinal implants, both from teams at Stanford University.

Source: http://www.wired.co.uk/news/archive/2012-11/09/self-powering-ear-implants