Researchers create working biobattery to power hearing device
For the first time ever an actual device was powered by the ear itself, although it was the ear of a guinea pig. Scientists are saying that they have found a way to tap into the body’s own electrical energy to power small devices!
A team of researchers are saying the days of old fashioned hearing aids may be over. They have created an experimental chip planted in the inner ear that gets its energy from the body itself.
Tina Stankovic, an auditory specialist and neuroscientist with Harvard University, headed the team that created the self-powered device in conjunction with MIT’s Microsystems Technology Laboratory. She stated that we could easily see some form of autonomous power for cochlear implants in the foreseeable future. The team was able to develop a small electronic chip with numerous low resistance electrodes that are able to grab infinitesimal amounts of the inner ear’s electrical activity.
While the technology seems straightforward enough, harnessing this small amount of power in the human body for long durations will be a challenge. That amount of energy made with our nerves is very small. Stankovic says that while science has known about the DC power in the human body for decades no one has even attempted to harness it until now.
(A close up of the tiny device that was implanted into the guinea pig's inner ear.)
“In the past, people have thought that the space where the high potential is located is inaccessible for implantable devices, because potentially it’s very dangerous if you encroach on it,” 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.”
For nerve cells to operate they must use a positively charged sodium and potassium ion across the membrane to create a very small electrochemical gradient. Stankovic says that the inner ear has that same process in the cochlea as well. It works by borrowing from the mechanical energy created on the eardrum and then converts it to electrical signals for the brain where it deciphers what was heard.
Stankovic and her team ran the first test and only test so far on a guinea pig’s inner ear. Electrodes were connected to both sides of its cochlea cell membranes, and then the device was connected to a small radio transmitter and monitored.
The guinea pig’s hearing was determined to be normal during the test, but it was only able to transmit just under 5 hours. The team said that the technology can work for short durations; however, there is a risk of damaging the fragile tissue inside the inner ear for any longer. Nevertheless, the device is proof of concept that such a technology can be attained.
In the very near future the team plans to minimize the device so there will be little or no chance of the inner ear being harmed. The team also speculates that as the technology progresses there may be a way of harnessing the energy stored in individual cells all throughout the human body to power other types of devices.