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Can you imagine having a skeleton made of glass? The sea sponge known as Venus’ flower basket can! Its skeleton is made of silica, the main material in sand and glass. This glass skeleton has inspired Australian engineers to create a strong new material that could make buildings more sustainable.

Sea sponges are animals that sit on the ocean floor and catch food that floats by. This sea sponge grows to between 10cm and 30cm tall and looks a bit like a basket. Its skeleton weaves together to form a fine mesh. And, if you look closely, it has a repeating pattern: squares criss-crossed with diagonal lines. This pattern gives the sea sponge a surprisingly strong body. It also allows it to get smaller when squashed, which is an ability called “auxetic” (awk-SEE-tick).

“While most materials get thinner when stretched or fatter when squashed, auxetics do the opposite,” says Jiaming Ma from RMIT University in Australia.

Tendons are another example of a natural auxetic material. You can feel the Achilles tendon at the back of your ankle. It attaches your calf muscle to your heel. Auxetic materials can absorb lots of energy from impacts, which is important for protecting your bones when you run. An auxetic skeleton allows the Venus’ flower basket to withstand the pressures of living deep below the surface of the ocean.

Jiaming and his team wanted to see if they could mimic these abilities. So, they 3D-printed the skeleton pattern out of plastic. They found that their sponge-inspired material is 13 times stiffer, and absorbs 10% more energy, than any other auxetic material ever made in a lab!

This means that the sponge-inspired material could be useful for lots of different things, like lightweight sporting equipment. Jiaming is especially excited about using it in buildings. Because the skeleton pattern is so stiff and strong, less steel and concrete would be needed to support a building. And using less material would be more sustainable.