Case Wester Reserver University researchers are developing a new plastic inspired by sea cucumber skin that could lead to safer brain implants or even clothing that hardens into armor with the flick of a switch. Sea cucumbers have skin that can switch between soft and rigid in seconds thanks to enzymes that bind the proteins fiber, and others that cause those binds to release. The new material is triggered by water but doesn't soak up the liquid like sponges or cardboard. From New Scientist:
"We have the elastic polymer, so that's the mimic for the sea cucumber skin, and then we put in the cellulose whiskers," (Stuart) Rowan says. "You can get these from paper pulp, but we got ours from another little sea creature called a tunicate."Link
When dry, the cellulose fibres keep the material rigid by forming a scaffold held together by hydrogen bonds. But water molecules are better at forming such bonds, so when wet, the fibres lose their grip on one another and bond to the water molecules instead...
The rigid material could easily be inserted into brain tissue, before softening into its floppy state. That would reduce the problems with inflammation solid electrodes can cause.
Rowan says they're now working on versions of the material that switch stiffness in response to a pulse of electricity.