Researchers at Cambridge University are considering the potential of more sustainable building materials -- the materials that will build the next generation of cities. One possible solution: synthetic bone.

Concrete and steel are the backbone of urban infrastructure, but in a warming climate, the two materials aren't sustainable. The production processes of each material are energy intensive. Both are responsible for significant amounts of greenhouse gas emissions.

While other researchers look to make steel and concrete more eco-friendly, Cambridge scientists are looking for inspiration from nature -- like bones and eggshells.

"What we're trying to do is to rethink the way that we make things," Michelle Oyen, a bioengineer at Cambridge, explained in a news release. "Engineers tend to throw energy at problems, whereas nature throws information at problems -- they fundamentally do things differently."

Oyen is an expert in biomimetics, the science of recreating natural materials in the lab. She and her colleagues are currently working to produce synthetic bone and eggshell and test their potential as building materials. Both materials are made from different ratios of mineral and protein. Mineral content provides the rigidity and strength, while protein offers durability.

Oyen and colleagues are devising methods for depositing mineral components onto collagen, one of the most common animal proteins.

"One of the interesting things is that the minerals that make up bone deposit along the collagen, and eggshell deposits outwards from the collagen, perpendicular to it," said Oyen. "So it might even be the case that these two composites could be combined to make a lattice-type structure, which would be even stronger -- there's some interesting science there that we'd like to look into."

Synthetic materials that mimic bone hold promise, but convincing the construction industry to adopt new materials will take time. In the meantime, environmental engineers and experts in sustainable architecture say we need to use sustainable materials as often as possible -- even wood.

Dr. Michael Ramage, a researcher at Cambridge's Department of Architecture, is focused on the use of wood for tall buildings, recently developing a plan for an 80-story timber skyscraper.

"The fundamental premise is that timber and other natural materials are vastly underused and we don't give them nearly enough credit," he said.