Researchers at the Huazhong University of Science and Technology in China created a battery-free device that could pave the way for an artificial cochlea to aid with hearing loss. The cochlea, a component of the inner ear, converts sound waves into electrical impulses, and the new device performs a similar function. The device consists of barium titanate nanoparticles within a conductive polymer to form a piezo-triboelectric material that generates an electrical signal when moved and jostled by sound waves.
For many people who are hearing impaired, the issue may lie in damage to the tiny hairs in the cochlea that help to convert sound waves to an electrical signal that the brain can recognize and interpret. This damage is typically irreversible and a device that can be inserted or implanted into the ear may be the best option to restore hearing. This situation has inspired researchers to attempt to develop an artificial cochlea, but currently such devices require an external power source, such as a battery, meaning that they may be bulky or require replacement.
To address this, these Chinese researchers have developed a self-powered piezo-triboelectric device that may pave the way for the artificial cochleas of the future. The technology consists of barium titanate nanoparticles coated with silicon dioxide, which the researchers mixed into a conductive polymer. They then processed the material so that it had a sponge-like consistency, allowing the nanoparticles to jostle about when sound waves struck the material, resulting in an electrical charge.
The idea is that as sound waves strike the device in the ear, it will generate a corresponding electrical charge that can be interpreted by the brain. To make the implant as useful as possible, the researchers designed it so that it could produce a maximum electrical signal at 170 hertz, which is within the range of an adult’s voice.
So far, the team tested the device within a model ear by playing a piece of music and then converting the corresponding electrical signal generated by the device into a new music file. They report that the piece of music was recognizable when playing the new music file, suggesting that the device was accurately converting the sounds to an electrical signal.
It will take further development before the technology is good enough to be used as an artificial cochlea, but the way forward is a little clearer.
Study in ACS Nano: Acoustic Core–Shell Resonance Harvester for Application of Artificial Cochlea Based on the Piezo-Triboelectric Effect