Researchers from the University of Akron discovered that spider silk will stretch and contract due to changes in environmental humidity, and will do so with a substantial amount of force. They believe that utilizing this property may allow for building of artificial muscles using a material that already has impressive strength and durability.
Michael Berger at Nanowerk explains:
The calculations by [Ali] Dhinojwala’s and [Todd] Blackledge’s team showed that silk generates work 50 times greater than the equivalent mass of human muscle. The researchers point out that these numbers are also much better than most of the synthetic materials developed so far.
The researchers hypothesize that water molecules cause a general swelling of the silk and their removal during drying results in contraction.
“This is strikingly similar to the mechanism proposed to explain how plant tissues can act as motors – actively expelling seeds from the parent plant and even burying seeds in the ground,” explains Dhinojwala. “For instance, differential expansion and contraction on opposite sides of the cellulose awns of wheat seeds causes them to bend under daily fluctuations of humidity thereby burying the seeds in the ground. Thus, cyclic contraction of spider silk may result from a relatively general response of biological tissues to humidity.”
Read on at Nanowerk…
Abstract in Journal of Experimental Biology: Spider silk as a novel high performance biomimetic muscle driven by humidity
Image credit: Tice Lerner…