LEWISTON — On a recent morning at Bates College, 19 students conducted an experiment that focused on one part of a furry feline’s body: the tongue and its capabilities.

The setting combined an experiment with a new design for a hair brush in a class led by assistant professor Andrew Mountcastle of Brunswick.

The course, Bioinspiration and Biomimetics, is the first of its kind at Bates College and the first time it’s been offered at the school.

According to the course description, students “explore examples of biological form and function, and use this knowledge to design a product that is inspired by nature to solve a problem faced by today’s society.”

Mountcastle said his class incorporates experiments that students can relate to the human and natural world.

“In this class, I’m trying to introduce my students to various case studies of bio-inspired design and how engineers and scientists have been inspired by biological structure to design or improve upon the design of something in the real world,” he said.

Mountcastle said he became interested in the effectiveness of cat tongues after reading a scholarly article, “Cats use hollow papillae to wick saliva into fur,” which was written by Alexis C. Noel and David L. Hua, his colleagues at Georgia Tech University. The article argued that a brush modeled to mimic a cat tongue required less force than a standard brush to get through a section of hair.

“That article really gave me the idea to use this as a project for this new class,” Mountcastle said. “It is a recent study and there was a timeliness to it, but it was also a fun exercise to have the students take on a project from observing a natural structure all the way to designing a tool that could be useful in the real world.”

According to Mountcastle, the start-to-finish process took nearly four weeks.

Equipped with a 3D printer and design software, Mountcastle had the students design brushes that mimicked a cat’s tongue, and brushes that were different than the feline salivatory organ.

But first, the students examined cats’ tongues under a microscope.

In particular, they looked at papillae, which are tiny scoop-shaped structures that help the animals be the effective groomers they are. The papillae also give the cat’s tongue its sandpaper-like texture.

Using the computer program SketchUp, the students designed two brushes: one that mimicked a cat’s tongue as closely as possible and another with some modifications.

“I had them manipulate an aspect of the design, so some groups chose to change the length of the papillae, some of the students changed the layout of each individual papillae relative to each other, and some groups chose to change the curvature of the papillae,” Mountcastle said.

Ruth Van Kampen, a senior from Brunswick, and her lab partner, Josh Turner, noticed under the microscope that there were hundreds of small scoops on the end of a real cat’s tongue. So they designed their modified brush without scoops.

“We were interested in the scoop because it seemed like a really tiny aspect of the design to really have any significance, and the scientific article our professor had us read mentioned that the scoops are used to wick the cat’s saliva onto the fur,” Van Kampen said. “But we weren’t using saliva in our experiment or anything like it, so we were wondering if it actually helped reduce the force it took to drag the brush through the fur because we thought it was just related to the saliva.”

Van Kampen and Turner tied weights to a rectangular plastic brush and let it fall through a piece of synthetic fur, mounted vertically on a wooden contraption.

They huddled around, pulling their brushes through “fuzzy fur,” (synthetic fur Mountcastle bought at Hobby Lobby) several times to see how much hair came out.

Van Kampen and Turner noticed the scooped cat tongue-inspired brush seemed to require less force to get through the fur than their scoopless brush did.

“At the beginning of this project I was expecting to have our scoopless brushes that we modified to pull through better because they had less surface area,” Van Kampen said.

“But, when I thought about it more, I realized that cats have had the opportunity to evolve over millions of years and cats have been able to live and survive more effectively,” she said, “so it makes sense that the more-cat-like tongues we had designed would pull through because that is what evolution has selected for and that’s how cats tongues are now.”

Van Kampen and the other students will be doing similar projects soon and the students will have a chance to weigh-in on what those projects will entail.

“After we get back from our winter break, I will be asking students what some of their ideas are for projects and we will continue to use the 3D printer to design and help us conduct our class experiments and relate them to the real world,” Mountcastle said.

From left, Bates College students Joseph Ho, Gavin Chen, and Brianna Karboski measure the fur that each of their cat-tongue-inspired brushes picked up. (Phyllis Graber Jensen / Bates College)

Bridget Tweedie tests how effectively a brush pulls raisins, meant to represent fleas, from a piece of synthetic fur, while her lab partner, Wendy Memishian, prepares to record data. (Phyllis Graber Jensen / Bates College)

Each student group in the Bates College class led by assistant professor Andrew Mountcastle of Brunswick made a brush modeled on a real cat tongue, as well as a brush with a modification. (Phyllis Graber Jensen / Bates College)


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