The sea cucumber has recently garnered attention for its unique skin structure. A scavenger par excellence, this leathery creature slithers slowly along the ocean floor, vacuuming up scraps of food. Though its plodding pace and soft flesh would seem to make it easy prey for a predator, it harbors a secret defense: a network of ultrathin cellulose fibers embedded in its skin. When threatened, the sea cucumber stiffens its skin by flooding the network with proteins that bind the fibers together, forming a solid structure.
Case Western University chemist Christoph Weder has developed a biopolymer that, like the sea cucumber's skin, can change from stiff to supple in an instant. The novel material stays rigid, thanks to an embedded web of fibers, until exposure to water ruptures the bonds holding the fibers together (when the water evaporates, the bonds reform). Researchers hope the material could one day be used to replace metallic, implanted neural electrodes with biopolymer electrodes that soften as soon as they touch moist neural tissue, thus avoiding damage to the fragile brain.