Researchers at Case Western Reserve University are testing models of a squid’s beak, which is harder than human teeth but soft at the base, to make medical devices safer and more comfortable for patients.

“There are all sorts of places in medicine where we’re using hard materials but we’re mostly soft,” Paul D. Marasco, principle investigator at the Advanced Platform Technology Center at the Louis Stokes Cleveland Department of Veterans Affairs Medical Center, stated in a press release. “Prosthetic limbs are connected to the arm or leg with a socket of hard plastic that fits over the residual limb. But bone moves around under the socket and can damage the soft tissue inside, while the socket can be hard on the skin where it makes contact.”

Marasco and colleagues are using a material that mimics a sea cucumber’s skin, which is soft and pliable when wet and stiff and hard when dry, in the form of a film and crosslinking it with nanofibers to maintain stiffness when wet. One end of the film was exposed to no light to ramp up stiffness across the film, while subsequent sections were exposed to increasingly more light to form more crosslinks.

The researchers found the grade from soft to hard was steeper when wet, just like a squid’s beak. Water switches off the weaker non-covalent bonds that form when the material is dry. According to the researchers, this technology is attractive for implants as the wet environment inside the body will enhance the gradient as well.

“We’re mimicking the architecture and the water-enhanced properties of the squid to generate these materials,” Stuart J. Rowan, the Kent H. Smith professor of macromolecular science and engineering at Case Western Reserve University, stated. “Now that we have shown that the concept works we’re now getting a bit more complicated and targeting materials that will allow us to move closer to applications.”

For more information:

Fox JD. J Am Chem Soc. 2013;135:5167-5174.

Disclosure: The researchers have no relevant financial disclosures.