Hearing Aid, Smartphone Microphones Could Get Better With Spider Silk

Introducing spider silk in your ears could do wonders for your hearing, a new study found. Not directly, of course, but spider silk in microphones makes them a lot more sensitive, potentially improving hearing aids, the study said.

Human hearing is based on the drums inside our ears picking up direction of sounds, depending on the pressure exerted on the drums by air. This is in contrast with several insects, most of which use their hair to pick up the velocity (speed and direction) of the air instead of its pressure. The fine hair on the bodies of flies, mosquitoes and spiders all move when they come in contact with sound waves in the air.

This inspired Ron Miles, professor at Binghamton University, New York, and graduate student Jian Zhou to try replicate that property in microphones by using spider silk.

“We coated the spider silk with gold and put it in a magnetic field to obtain an electronic signal. It’s actually a fairly simple way to make an extremely effective microphone that has better directional capabilities across a wide range of frequencies,” Miles said in a statement Monday, explaining how they translated the information gathered by spider silk into electronic signals.

Since spider silk is sensitive to a very wide range of sounds, from infrasound to ultrasound (below and above the human range of hearing), the microphone created by Miles and Zhou is superior than existing technology in “directional sensing across a wide variety of frequencies,” some of which are too faint to be picked up present-day microphones. In fact, spider silk is sensitive to frequencies as low as 3 hertz, Miles said, which is equivalent to being able to hear the sound of tectonic plates moving during an earthquake.

These properties mean the spider silk-infused microphone can allow someone using a hearing aid to cancel out the background noise when in a crowded place to have a smoother conversation. And the concept is not restricted to hearing aids, but can be used in microphones in smartphones as well.

And this property is not limited to spider silk alone, but will likely be exhibited by any fiber that is thin enough, Miles said.

“The results are significant because they elucidate the highly responsive nature of materials such as spider silk. This bioinspired approach will be valuable to various disciplines which have been pursuing miniaturized flow measurement and control in various mediums (air, gas, liquid) and situations (from steady flow to highly fluctuating flow),” the authors said in the study, which appeared online in the journal Proceedings of the National Academy of Sciences, under the title “Sensing fluctuating airflow with spider silk.”

Inspiration from other species, especially animals, is called biomimicry and is used in many scientific and technological developments, very often in the field of robotics.