Instead of concrete and steel, cities of the future may need to be built from artificial bone and eggshell in order to support a growing population and save the environment, a new study suggests.

Building standards of today are drawn up with concrete and steel in mind, but these materials are actually responsible for a number of carbon emissions worldwide, experts said.

In fact, before these materials reach a construction site, both steel and concrete are processed at extremely high temperatures, taking a lot of energy. And yet, cities today are entirely dependent on these materials.

Artificial Eggshell And Bone As Building Materials

Some scientists are either finding more sustainable methods to produce steel and concrete or looking for ways to use them less, but bioengineers at the University of Cambridge took a different approach.

Led by Michelle Oyen, researchers prefer a complete change: create new materials that are not only strong but sustainable, too. They took their inspiration from nature.

"What we're trying to do is to rethink the way that we make things," she says.

In her laboratory, which is funded by the United States Army Corps of Engineers, Oyen constructs small samples of artificial bone and eggshell. These sustainable materials can be used as medical implants and can even be turned into low-carbon building materials.

These are ideal materials because of their characteristics. The proportion of proteins and minerals in bones is approximately equal, giving it stiffness and hardness, as well as toughness and resistance to fracture. Although bones can break, they have the added benefit of self-healing — a feature that bioengineers are trying to mimic.

On the other hand, the ratio of proteins and minerals in eggshells is at 5 percent and 95 percent, respectively, but even the tiny amount of protein makes it remarkably tough.

Because the process of making the artificial bone and eggshells takes place at room temperature, the samples need very little energy to be produced.

During manufacturing, the mineral components of the artificial bone and eggshells are directly templated onto collagen. Oyen says the composites could even be combined to make a lattice-type structure that would potentially be stronger. This is something they would like to investigate more.

Furthermore, the collagen that they will need to use comes from natural sources, such as animals. One of the things they will be studying is whether a synthetic or non-animal derived protein could be used instead.

Meanwhile, although the project is promising, researchers say we won't be seeing buildings made of artificial bone and eggshell soon.

Photo: Abdul Rahman | Flickr

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