A small, hard seed from Australia may help scientists design stronger and safer protective gear.
Researchers at New York University Abu Dhabi have been studying the marri nut, the seed of the marri tree found in Western Australia, and discovered why it is so incredibly tough.
Even animals that try to eat it often struggle to crack it open.
The secret lies in the nut’s clever internal design. Instead of being solid all the way through, the marri nut has a layered structure.
It combines a hard outer shell with a softer, more flexible interior.
This mix of strength and flexibility allows the nut to handle strong impacts without breaking. When force is applied, the energy spreads through the structure instead of causing a sudden crack.
This is very different from many man-made materials, which are often either hard or flexible, but not both.
If something is too hard, it can shatter under pressure. If it is too soft, it may not provide enough protection. The marri nut shows that combining both properties in one structure can lead to better performance.
The research team spent five years studying the nut using advanced imaging tools and mechanical tests.
They found that although the nut is mostly made of cellulose, a natural material found in plants, it behaves in a surprising way.
It can absorb energy like a soft material such as Teflon, while also staying stiff like harder materials such as acrylic. At the same time, it remains lightweight.
According to the researchers, the nut does not just resist damage by being strong. Instead, it controls how cracks form and spread.
When stress builds up, the structure guides any small cracks in a way that prevents the entire shell from failing. This controlled response helps the nut survive impacts that would break many other materials.
Inspired by this natural design, the team created a new material that copies the nut’s layered structure.
Their goal is to use this idea to improve products that need to absorb impact, such as helmets, protective gear, and safety equipment. Materials based on this design could be lighter, stronger, and better at protecting people from injury.
This study, published in the journal Advanced Science, shows how nature can offer valuable solutions to engineering challenges. After millions of years of evolution, plants like the marri tree have developed structures that balance strength and flexibility in ways scientists are only beginning to understand.
By learning from these natural designs, researchers hope to create new materials that are not only tougher but also smarter in how they respond to force.
