A strange new substance acts like a liquid when exposed to air, but takes a solid shape when it's dunked in water.
The new stuff is a metamaterial, scientists' word for a lab-made material that has properties that are uncommon in nature. Even among metamaterials, however, it's unusual — it's composed of man-made DNA, while most metamaterials are composed of nonbiological chemicals such as silicon or copper. Its creators are calling it a "meta-hydrogel."
In the future, metamaterials made of biological stuff could go into soft, flexible circuits, according to a statement from Cornell University, where the meta-hydrogel was made. Because they have pores in which drug molecules could fit, meta-hydrogels could help release medicines slowly inside the body, the statement said.
Adding to its unusual properties, the new meta-hydrogel remembers its original shape. If it's made in a mold, it will return to its original, molded shape every time it's doused in water, even after researchers expose it to air — and force it into its liquidlike state — several times. The researchers made a video that shows the meta-hydrogel firming up into letters when a researcher adds water to it.
To get the meta-hydrogel to take on a new solid shape, the gel’s creators heat it to 185 degrees Fahrenheit (85 degrees Celsius) and set it in new molds.
When a team of Cornell engineers first mixed the chemicals to make their meta-hydrogel, they didn't know it would act so strangely. "This was not by design," Dan Luo, the lead scientist in the research, said. Luo and his colleagues have used synthetic DNA to make hydrogels, or gels composed mostly of water, before. This time, they wanted to make a DNA hydrogel with a different microscopic structure. It was only after they created their meta-hydrogel that they discovered its unique abilities, the researchers wrote in a paper they published Dec. 2 in the journal Nature Nanotechnology.