Researchers at the Massachusetts Institute of Technology (MIT) have developed three new 3D-printed composite materials that mimic the characteristics of bone. The inspiration behind the new materials came from both bone and nacre (mother of pearl).

"The geometric patterns we used in the synthetic materials are based on those seen in natural materials like bone or nacre, but also include new designs that do not exist in nature," says Markus Buehler of the Department of Civil and Environmental Engineering. "As engineers we are no longer limited to the natural patterns. We can design our own, which may perform even better than the ones that already exist."

The first material they designed mimicked bone, the second simulated the mineral calcite and the third had a diamond shaped internal pattern intended to improve upon nature.

Each of the created samples is one-eighth of an inch thick and about 5-by-7 inches in size. The research team put them through a battery of tests to determine their fracture points. All three passed the tests with flying colors, though the bone-like sample proved to be the strongest.

"This research is a wonderful example of how 3D printing can be used to fabricate complex architectures that emulate those found in nature," says Jennifer Lewis, the Hansjörg Wyss Professor of Biologically Inspired Engineering at Harvard University. "The power of integrating design, computational modeling and 3D assembly will only be fully realized when these tools are combined to generate entirely new 'metamaterials' — in other words, ones that today do not exist in either engineered or biological forms. This work represents an important step toward this objective."

Buehler believes composite materials like these may one day be used to print buildings. "The possibilities seem endless, as we are just beginning to push the limits of the kind of geometric features and material combinations we can print," Buehler says.