Future Buildings Could be Made of Artificial Bone
This photo shows the brick-and-mortar pattern of simulated bone and nacre against the backdrop of real nacre found in the inner shell of many molluscs.
CREDIT: Graham Bratzel
Move over nanotubes, there's a new futuristic building material in town and its origins may surprise you.
Developed by researchers at the Massachusetts Institute of Technology (MIT), human bone is the inspiration behind the latest high-tech composite, which can be made in just a few hours using a 3D printer.
The new material — which is lauded for its durability, low density and environmentally sustainable constituents — gets its strength from its bone-like structure. Real bones have a complex hierarchical structure thanks to their two main building blocks, collagen protein and hydroxyapatite minerals.
MIT's new material replicates this hierarchical pattern, which is produced in bones with the help of electrochemical reactions. Such reactions are difficult to reproduce in a lab, but with a 3D printer, the researchers were able to replicate the fracture-resistant structure.
Under a microscope, the synthetic material the researchers created looks like a staggered brick-and-mortar wall. A soft black polymer serves as the mortar, simulating the work of collagen, bone's yielding cushion. A stiff blue polymer forms the bricks, behaving like hydroxyapatite, bone's strong but brittle frame.
And just as collagen and hydroxyapatite help a bone withstand fracturing by dissipating energy and distributing damage over a larger area, so too does the lab-made material. In fact, the material may prove to be even stronger than bone.
"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," said Markus Buehler, lead researcher in the study.
"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 3D-printed bone material is 22 times more fracture-resistant than any of its constituent parts, an impressive ratio for a lab-made composite.
Researchers suggest that the process of 3D printing super-strong metamaterials is both entirely possible and more cost-effective than traditional methods of manufacturing. Buehler hopes that one day, optimized materials like the one created in MIT's lab will form the basis of entire buildings.
"The possibilities seem endless," he said, "As we are just beginning to push the limits of the kind of geometric features and material combinations we can print."