Sea cucumber implant breakthrough

A new material inspired by the sea cucumber that switches from hard to soft states could have important uses in medicine, say scientists.
The lowly sea cucumber, which lives a languid life on the sea bed, normally has a soft and squishy body. But when threatened, it can instantly armour itself by hardening its skin.
Research has shown that the animal owes this ability to rigid collagen fibres embedded in pliable connective tissue.
Chemicals secreted by the creature's nervous system cause the fibres to form a reinforcing network, which stiffens the skin.
Taking a lesson from the sea cucumber, scientists in the US added fine cellulose fibres to a rubbery polymer mixture.
This produced a hard plastic-like material which turned soft on contact with water, due to bonds between the fibres being disrupted. Once it was dry again, the bonds reformed and the material hardened.
The polymer material could be used to improve the effectiveness of biomedical implants, especially those in the brain, the researchers report in the journal Science.
Brain implants that interact with nerves have been used experimentally in the treatment of Parkinson's disease, stroke and spinal cord injuries. However, they often fail within a few months.
It is thought the high stiffness of the electrodes, which is necessary for their insertion, causes damage to surrounding brain tissue over time.
Dr Dustin Tyler, from Case Western Reserve University in Cleveland, Ohio, who co-led the research, said: "We believe that electrodes that use mechanically adaptive polymer as a substrate could alleviate this problem."