Could the buildings of the future be grown, instead of built?

A, frankly pretty generic, lab pic, because our image archive is disappointingly short on biomimetic materials. Image: Getty.

As the world grapples with climate change, we urgently need to find ways of reducing our CO₂ emissions. Sectors which rely heavily on fossil fuels, such as energy and aviation, are commonly held to be the worst offenders.

But what most people don’t realise is that there’s another culprit, hiding in plain sight; on the streets of our cities, and in the buildings where we live and work.

In 2007 alone, steel and concrete were each responsible for more CO₂ emissions than the entire global aviation industry. Before reaching the construction site, both steel and cement must be processed at very high temperatures – and this takes a lot of energy.

So how can we reduce our dependence on these “dirty” materials, when they play such a crucial role in construction?

One option is to use natural materials, such as wood. Humans have been building with wood for thousands of years, and wooden structures are currently experiencing a minor resurgence – partly because it’s a cheap and sustainable material.

But there are some disadvantages to building with wood; the material can warp in humid conditions, and is susceptible to attack by pests such as termites. And while natural materials, such as wood, are appealing from an environmental perspective, they can be unsatisfying for engineers who might wish to make components in a specific shape or size.

Copying life

So what if, instead of using natural materials as we find them, we make new materials that are inspired by nature?

This idea started to gain traction in the research community in the 1970s and really exploded in the 1990s, with the development of nanotechnology and nanofabrication methods. Today, it forms the basis of a new field of scientific research: namely, “biomimetics” – literally “copying life”.

Biological cells are often referred to as “the building blocks of life”, because they are the smallest units of living matter. But to create a multi-cellular organism like you or me, cells must clump together with a support structure to form the biological materials we’re made of – tissues such as bone, cartilage, and muscle. It’s materials like these which scientists interested in biomimetics have turned to for inspiration.

In order to make biomimetic materials, we need to have a deep understanding of how natural materials work. We know that natural materials are also “composites”: they are made of multiple different base materials, each with different properties. Composite materials are often lighter than single component materials, such as metals, while still having desirable properties such as stiffness, strength and toughness.

Making biomimetic materials

Materials engineers have spent decades measuring the composition, structure and properties of natural materials such as bone and eggshell, so we now have a good understanding of their characteristics.

For instance, we know that bone is composed of hydrated protein and mineral, in almost equal proportions. The mineral confers stiffness and hardness, while the protein confers toughness and resistance to fracture. Although bones can break, it is relatively rare, and they have the benefit of being self-healing – another feature that engineers are trying to bring to biomimetic materials.

Like bone, eggshell is a composite material, but it is around 95 per cent mineral and only 5 per cent hydrated protein. Yet even that small amount of protein is enough to make eggshell very tough, considering its thinness – as most breakfast cooks will have noticed. The next challenge is to turn this knowledge into something solid.

There are two ways to mimic natural materials. Either you can mimic the composition of the material itself, or you can copy the process by which the material was made. Since natural materials are made by living creatures, there are no high temperatures involved in either of these methods. As such, biomimetic materials – let’s call them “neo-bone” and “neo-eggshell” – take much less energy to produce than steel or concrete.

In the laboratory, we have succeeded in making centimetre-scale samples of neo-bone. We do this by preparing different solutions of protein with the components that make bone mineral. A composite neo-bone material is then deposited from these solutions in a biomimetic manner at body temperature. There is no reason that this process – or an improved, faster version of it – couldn’t be scaled up to an industrial level.

Of course, steel and concrete are everywhere, so the way we design and construct buildings is optimised for these materials. To begin using biomimetic materials on a large scale, we’d need to completely rethink our building codes and standards for construction materials.

But then, if we want to build future cities in a sustainable way, perhaps a major rethink is exactly what’s needed. The science is still in its infancy, but that doesn’t mean we can’t dream big about the future.The Conversation

Michelle Oyen is a reader in bioengineering at the University of Cambridge.

This article was originally published on The Conversation. Read the original article.


Coming soon: CityMetric will relaunch as City Monitor, a new publication dedicated to the future of cities

Coming soon!

Later this month, CityMetric will be relaunching with an entirely new look and identity, as well as an expanded editorial mission. We’ll become City Monitor, a name that reflects both a ramping up of our ambitions as well as our membership in a network of like-minded publications coming soon from New Statesman Media Group. We can’t wait to share the new website with you, but in the meantime, here’s what CityMetric readers should know about what to expect from this exciting transition.  

Regular CityMetric readers may have already noticed a few changes around here since the spring. CityMetric’s beloved founding editor, Jonn Elledge, has moved on to some new adventures, and a new team has formed to take the site into the future. It’s led by yours truly – I’m Sommer Mathis, the editor-in-chief of City Monitor. Hello!

My background includes having served as the founding editor of CityLab, editor-in-chief of Atlas Obscura, and editor-in-chief of DCist, a local news publication in the District of Columbia. I’ve been reporting on and writing about cities in one way or another for the past 15 years. To me, there is no more important story in the world right now than how cities are changing and adapting to an increasingly challenging global landscape. The majority of the world’s population lives in cities, and if we’re ever going to be able to tackle the most pressing issues currently facing our planet – the climate emergency, rising inequality, the Covid-19 pandemic ­­­– cities are going to have to lead the way.

That’s why City Monitor is going to be a global publication dedicated to the future of cities everywhere – not just in the UK (nor for that matter just in the US, where I live). Our mission will be to help our readers, many of whom are in leadership positions around the globe, navigate how cities are changing and discover what’s next in the world of urban policy. We’ll do that through original reporting, expert opinion and most crucially, a data-driven approach that emphasises evidence and rigorous analysis. We want to arm local decision-makers and those they work in concert with – whether that’s elected officials, bureaucratic leaders, policy advocates, neighbourhood activists, academics and researchers, entrepreneurs, or plain-old engaged citizens – with real insights and potential answers to tough problems. Subjects we’ll cover include transportation, infrastructure, housing, urban design, public safety, the environment, the economy, and much more.

The City Monitor team is made up of some of the most experienced urban policy journalists in the world. Our managing editor is Adam Sneed, also a CityLab alum where he served as a senior associate editor. Before that he was a technology reporter at Politico. Allison Arieff is City Monitor’s senior editor. She was previously editorial director of the urban planning and policy think tank SPUR, as well as a contributing columnist for The New York Times. Staff writer Jake Blumgart most recently covered development, housing, and politics for WHYY, the local public radio station in Philadelphia. And our data reporter is Alexandra Kanik, whose previous roles include data reporting for Louisville Public Media in Kentucky and PublicSource in Pittsburgh, Pennsylvania.

Our team will continue to grow in the coming weeks, and we’ll also be collaborating closely with our editorial colleagues across New Statesman Media Group. In fact, we’re launching a whole network of new publications this fall, covering topics such as the clean energy transition, foreign direct investment, technology, banks and more. Many of these sectors will frequently overlap with our cities coverage, and a key part of our plan is make the most of the expertise that all of these newsrooms combined will bring to bear on our journalism.

City Monitor will go live later this month. In the meantime, please visit to sign up for our forthcoming email newsletter.

As for CityMetric, some of its archives have already been moved over to the new website, and the rest will follow not long after. If you’re looking for a favourite piece from CityMetric’s past, for a time you’ll still be able to find it here, but before long the whole archive will move over to City Monitor.

On behalf of the City Monitor team, I’m thrilled to invite you to come along for the ride at our forthcoming digs. You can already follow City Monitor on LinkedIn, and on Twitter, sign up or keep following our existing account, which will switch over to our new name shortly. If you’re interested in learning more about the potential for a commercial partnership with City Monitor, please get in touch with our director of partnerships, Joe Maughan.

I want to thank and congratulate Jonn Elledge on a brilliant run. Everything we do from here on out will be building on the legacy of his work, and the community that he built here at CityMetric. Cheers, Jonn!

In the meantime, stay tuned, and thank you from all of us for being a loyal CityMetric reader. We couldn’t have done any of this without you.

Sommer Mathis is editor-in-chief of City Monitor.