Can you imagine a plastic that can change from hard to soft in a matter of seconds when exposed to a liquid?

That's what researchers at Case Western Reserve University in Cleveland have developed. They're comparing the material to something already found in nature: sea cucumbers.

"These creatures can reversibly and quickly change the stiffness of their skin. Normally it is very soft, but, for example, in response to a threat, the animal can activate its 'body armor' by hardening its skin," said Jeffrey Capadona, associate investigator at the Louis Stokes Cleveland Department of Veterans Affairs Medical Center, which worked on the development with researchers from Case's departments of macromolecular science and engineering and biomedical engineering.

According to a news release from the university, marine biologists have shown in earlier studies that the hard-to-soft switching effect in sea cucumber's biological tissue "is derived from a distinct nanocomposite structure in which highly rigid collagen nanofibers are embedded in a soft connective tissue. The stiffness is mediated by specific chemicals that are secreted by the animal's nervous system and which control the interactions among the collagen nanofibers. When connected, the nanofibers form a reinforcing network which increases the overall stiffness of the material considerably, when compared to the disconnected (soft) state."

The team used nanocomposites in their artificial version of the polymer, too, and they believe the material will have biomedical applications, such as in devices that help treat patients that suffer from Parkinson's disease, stroke or spinal cord injuries.

Their research also is featured in the journal Science.