From the sea floor to the surgical suite

Scientists at Case Western Reserve University are improving brain studies thanks to an attribute of the sea cucumber.  

This starfish relative looks a lot like its namesake -  a sand-sifting pickle on the sea floor.  And the sea cucumber is on a lot of predator’s menus.  That’s why biomechanical engineer Jeff Capadona says the creature developed two ways to defend itself. The first makes it unpalatable by suddenly stiffening its outer layer through a change in the chemistry of its skin –

“…and that’s the mechanism that we’re really trying to play on.  The other is that it spits out its internal organs and becomes toxic.  We’re not trying to replicate that.”

Brain researcher and team leader Dustin Tyler, who today has a bit of laryngitis, recalls a conversation years ago where a colleague from another department wondered –

“What if we made a material like this”   …A material that, like the sea cucumber, could become stiff or soft with a chemical command.  It became Tyler’s goal.

“We know how the sea cucumber worked but to take it from the biologic model, which is incredibly complex, to what we could functionally utilize has been many years and many steps to do that.”

Now Tyler and Capadona have developed brain probes using a synthetic version of the sea cucumber’s skin.

“So this grew out of just a bunch of us sitting around a table throwing out ideas about what we wanted to do.”

Building a better brain probe

Tylers brain lab looks like a high tech-surgical suite, but his patients are rats. 

He fires up the machines used to put the subjects to sleep, and the sensitive electrical equipment he uses to communicate with individual neurons inside the rat’s brain. 

“We can manipulate for example the whisker, and we can implant where we know that is.  As you vibrate that, that cell will start to activate more.”

In his work, Tyler inserts a tiny probe inside the animal’s brain to measure the minute electrical impulse that fires when he moves a rat’s whisker.  

“The analogy of the human would be: I want to find out what sensation area of the skin, like I touched your finger. Where in the brain is that responding? That’s what we’re doing on a model that we understand.”

Tyler and his team are using this research to help doctors at Cleveland’s VA hospital develop new therapies for spinal cord-injury patients.  The brain probes will allow doctors to bypass the damaged spinal cord to allow conscious movement. 

“We can record that thought from you brain, translate it to a device that we can stick in your arm to actually control the muscle that controls your hand.”

Which brings us back to the sea cucumber.

Dustin Tyler has found that brain probes coated with synthetic sea cucumber skin are stiff enough to push into the brain, but then become soft, which means less scarring.  Less scarring allows for better communication between the neuron and the sensitive probe.

Jeff Capadona , who came to Case from Georgia Tech to develop the sea cucumber probe with Tyler, now specializes in biocompatible materials.

“Because, as Dustin always says, everything exciting happens at the interface, whether it’s between disciplines, or between the body and a device, or anything else.”

The Case team published its findings in the online edition of the Journal of Neural Engineering.

I’m Jeff St. Clair with this week’s Exploradio.