A new material made from synthetic DNA is so soft that it can flow like a liquid and then return to its original shape.
This new hydrogel is made of synthetic DNA. Previously, by synthesizing DNA with carefully arranged complementary sections, the research team created short stands that link into shapes such as crosses or Y’s, which in turn join at the ends to form mesh-like structures to form the first successful all-DNA hydrogel.
When trying a new approach, researchers mixed synthetic DNA with enzymes that cause DNA to self-replicate and to extend itself into long chains, to make a hydrogel without DNA linkages. During this process they entangle, and the entanglement produces a 3D network. But the result was not what they expected: The hydrogel they made flows like a liquid, but when placed in water returns to the shape of the container in which it was formed.
Exactly how this works is still being investigated. The scientists theorize that the elastic forces holding the shape are so weak that a combination of surface tension and gravity overcomes them; the gel just sags into a loose blob. But when it is immersed in water, surface tension is nearly zero—there’s water inside and out—and buoyancy cancels gravity. Read more here:
http://bit.ly/YAVTg0Journal article: A mechanical metamaterial made from a DNA hydrogel. Nature Nanotechnology, 2012.
http://dx.doi.org/ 10.1038/nnano.2012.211
