When you think of earwax, what comes to mind? Sticky, gunky, yuck... What if I told you that the future of robotics could involve earwax... you would think that's crazy, right?
Georgia Institute of Technology's doctoral student Alexis Noel discovered that earwax could potentially be a template for developing adhesives for applied usage in robotics or other kinds of technology.
Noel's discovery of earwax's potential began with a trip to the emergency room with her boyfriend. After Noel's boyfriend went on a diving vacation, water became trapped in his ear, resulting in earwax impaction.
"A couple years later, I was reminiscing and thought: why would it block the water like that? And it just started this snowball effect of me and David [Hu] just asking questions about earwax and how it works," Noel said.
The study appears in the journal Society for Integrative and Comparative Biology.
Keep reading to see what the research found...
How it Happened
Georgia Tech scientist David Hu and undergraduate researcher Zac Zachow teamed up with Noel to study earwax by collecting samples from several animals including pigs, sheep, rabbits, and dogs.
Her team of scientists discovered that the properties of earwax are extremely consistent across different types of mammals, which have a variety of ear shapes and sizes. The thickness, the way earwax flows, and even the appearance is highly similar between different mammals.
Their research indicated that the protective properties of earwax seem to be a solution that works well across species.
Earwax As a Filter
Noel discovered that earwax is a non-Newtonian, shear-thinning fluid, which means that when earwax is left alone, it is very thick and sticky, comparable to molasses. However, when force is applied to earwax, it flows more rapidly.
As a result, although earwax works within the ear for a while, pressure, and motion of the jaw will eventually force it out, similar to a "conveyer belt" type process.
In the ear, earwax is the perfect filter for air. Earwax traps other foreign invaders in a "web" of small hairs coated with sticky wax which protects the inner ear.
The researchers also found that earwax becomes crumbly when it accumulates dust.
"Like adding too much flour to the dough when making bread," Noel said. This self-cleaning property allows the dusty wax to dry up and fall out of the ear, making room for new wax to continue its work within the ear.
Earwax's filtering properties sparked Noel's interest for its practical applications.
One potential is to create a type of biomimetic earwax adhesive surface that can be utilized in a ventilation system for robotics or for other kinds of machinery; therefore, creating high-tech filters.
"Obviously you're not going to have earwax sitting on a Mars rover to protect it from dust," said Noel. "We are still trying to understand what earwax is, and how it works. And once we really understand that we can start applying it [to new technology]."