Seashells or spider silk: how nature could transform the structure of cities

In the race to replace concrete and steel, bioengineers and architects are experimenting with alternatives including blood, bone and eggshells

Ask the Cambridge bioengineer, Michelle Oyen, how the cities of the future might look, and she'll reference termite mounds, along with the swirling architecture of Antoni Gaudi, whose buildings look like they've grown from organic matter rather than been built by human hands. Oyen and her contemporaries are currently striving to harness nature's smart building techniques, investigating bone, eggshell, seashells and spider silk, as alternatives to unsustainable steel and concrete.

"As engineers," she says, "we throw energy at problems to make things technologically better, but we don't necessarily think about the consequences of what all of that energy input is doing." The concrete industry, for example, produces 5% of global CO₂ emissions. The beauty of the materials that Oyen and colleagues are developing is that they can be produced in gentle, low-energy conditions.