Future Cities

Swapping steel & concrete for buildings of bone

By Kitty Knowles 7 March 2016
Guadi Casa Milà. Pic: iStock/Brzozowska

New organic materials could drastically change our skylines for the better.

Did you know that our concrete jungles could well be grown in the future?

Scientists like Dr Michelle Oyen, a bioengineer at Cambridge University, are currently busy growing new materials that could cut our carbon emissions and drastically change our skylines.

“I’ve been saying for years that we should be building materials out of bone or egg shell that is grown in labs,” Oyen told The Memo, ahead of her lecture, ‘Rethinking How We Build Stuff’, at the Cambridge Science Festival.

“There’s a huge potential to make a very large global CO2 emissions impact by thinking about using different materials in the construction industry.”

A return to nature

We’ve long looked to nature for aesthetic inspiration, but the natural sciences should also be looked to for practical solutions, says Oyen.

“What Gaudi was doing was more of an aesthetic thing, but you can take this further,” she explains.

“There’s been a lot of speculation, for example, about how termite mounds – which have very intricate cooling systems inside – could potentially be used to design new ventilation systems for buildings.”

Credit: The Rockerfeller Foundation.
Credit: The Rockerfeller Foundation.

Growing new materials

An extension of this is the development of biomimetic materials: synthetically ‘grown’ materials that are inspired by nature.

“We’re already growing biomimetic materials in small quantities for proof of concept,” says Oyen. Indeed, some products have already come to market.

“There are some fabrics that are mimicked after butterfly wings,” explains Oyen. “Some butterflies, especially the very blue ones are not because of pigment, but by the actual structure within the wings.”

“There’s paint that’s based on the structure of lotus leaves that sheds water, so it’s become self cleaning,” she adds. “The University of Florida, has even developed Sharklet, an organically antimicrobial materials that could be used to cover surfaces in hospitals.”

Morpho peleides butterfly. Pic:istock/AndreaPad77
Morpho peleides butterfly. Pic:istock/AndreaPad77

The benefits of building out of bone

Biomimetic materials would make great building materials because they can combine unusual properties, says Oyen. “You end up growing something that is itself a composite, that has both mineral and protein components,” she explains.

“Like natural materials, they are stiff and strong for their weight; We build very modern airbus airplane out of them because they give you combinations of properties that you can’t get from a single material.”

In the future we could grow whole girders out of bone, adds Oyen.

“We make little pieces of artificial bone in the lab, but the idea is to think about whether can we scale this up to build things like girders that normally might be made out of pretension steel, or concrete.”

Pic: Scientists have used shark cells (centre) to inspire a new biomimetic material called Sharlket (right).
Pic: Scientists have used shark cells (centre) to inspire a new biomimetic material called Sharlket (right).

Creating a recyclable world

These new materials could also be good for the environment. Huge amounts of energy are used to create materials like steel and concrete, with energy from fossil fuels consumed in the construction industry accounting for around half of the UK’s emissions of carbon dioxide. (This figure is even higher in the US).

“You process concrete and steel at very high temperatures; there’s a lot of energy that goes into the processes,” says Oyen.

At the other end of the scale, harnessing the power of nature means that bioengineered materials can grow with relatively little energy input.

“Natural materials are made in very low energy ways – that’s how biology does things,” explains Oyen. “There’s also an element of recyclability – of ashes to ashes and dust to dust. If you build things out of natural materials they can eventually go away.”

How can we get there?

While we’re not growing biomimetic girders just yet, it’s a case of thinking big, says Oyen. Money and time needs to be ploughed into the field to develop the science, and bring it to life.

“We need to scale up,” says Oyen. “We need investment to develop these ideas and take them from the laboratory into mass production.”

“We have to rethink how we build things if we’re going to work on the problems that we’ve made in terms of global warming and CO2 emissions.

Bring on the egg shell cities of the future.

Dr Michelle Oyen will be delivering her lecture ‘Biomimetic materials: re-thinking how we build stuff‘ on Wednesday 9 March between 8pm – 9pm at the Mill Lane Lecture Rooms, Cambridge. Find out more about the Cambridge Science Festival.  

Read more: Cambridge Science Festival: Can iPhones grow on trees?

Read more: Cambridge Science Festival: 10 incredible pictures that will make you see science differently