Researchers have isolated chloroplasts before this, but these organic components tend to stop working a few hours after removal from a plant. The team made them more practical by significantly extending their useful lifespan.

There's more work to be done, such as replacing the chloroplasts with artificial catalysts that could achieve a similar effect. The potential applications are already clear, however. You could use the polymer as a building material that fixes itself while countering excessive CO2 emissions. It might function as a coating for other products, too. And it could even be economical -- construction crews could ship the material in liquid form and make panels out of it at the building site. Urban sprawl would still be a problem after this, but it might have its upsides for the planet.