Earwax may inspire high-tech filters, adhesives in robotics

Earwax, considered to be just an unappealing substance by most, may have potential as a high-tech filter or adhesive for use in robotics and other fields, scientists say.
Alexis Noel from Georgia Institute of Technology in the US realised that this strange bodily fluid could potentially be a template for developing adhesives for applied usage in technology.
She began investigating earwax by collecting samples from several animals - pigs, sheep, rabbits and dogs.
They found that the properties of earwax are extremely consistent across these different mammals, which have a variety of ear shapes and sizes.
The thickness, the way it flows, and even the appearance is highly similar. This indicates that those properties of earwax seem to be a solution that works well across species.

They also examined the ear canal shapes of different animals and motions of the jaw to see how these factors affect the flow of the earwax and lead to it falling out of the ear.

It turns out that earwax is a non-Newtonian, shear-thinning fluid, which means is that when left alone, it is very thick and sticky (earwax is as viscous as molasses), but when a force is applied to it, it flows more quickly.
As a result, although earwax is used within the ear for a long time, pressure and motion of the jaw will eventually force it out.

In the ear, earwax is excellent at filtering air. It traps other particles, catching them in a "web" of small hairs coated with sticky wax and protecting the inner ear from debris and bacteria.
Researchers have also found that as earwax accumulates dust, it becomes crumbly "like adding too much flour to dough when making bread," she said
This allows the dusty wax to separate and fall out of the ear, making room for newer, cleaner wax to continue its work within the ear.
It is these filtering properties that have piqued Noel's interest for practical applications.
One potential is to create some sort of biomimetic earwax adhesive surface that can be used in a ventilation system for robotics or for other kinds of machinery.

The study appears in the journal Society for Integrative and Comparative Biology.