A few years ago, Columbia University researcher Klaus Lackner generated a spray of headlines with designs for a band-shaped plastic kiosk that would capture carbon dioxide thousands of times faster than any tree.
But Lackner's "synthetic trees" wouldn't look anything like trees, nor would they be made of anything remotely organic. Let's say they lack the romance of the real thing.
Enter design student Julian Melchiorri, who claims to have made the "world’s first man-made biological leaf." Melchiorri extracted chloroplasts (the organelles that help a plant photosynthesize) from real botanical cells and infused them into a matrix made of silk. The result is a lovely, all-natural, little green shape, which Melchiorri says can capture carbon and produce oxygen just as a real leaf does.
Melchiorri isn't suggesting his leaves would function at the intensity or rate of Lackner's tree. But he does offer some pretty ambitious applications. Especially intriguing is his vision of plastering the leaves on the sides of buildings, which he says could increase oxygenated air for residents. The graphic demonstrating the idea is stunning, sort of like a stripped down version of Moshe Safdie's plant-draped "A-Frame Membrane Habitat" design.
Melchiorri also indicates that his product could be used to generate oxygen for astronauts. "Plants don't grow in zero gravity," he told design blog Dezeen. "NASA is researching different ways to produce oxygen for long-distance space journeys to let us live in space. This material could allow us to explore space much further than we can now."
That sounds great. But how possible would it be for silk-embedded chloroplasts to survive and photosynthesize on earth, let alone in space? We posed the question of just how viable Melchiorri's leaves are to Dr. Wim Vermaas of Arizona State University's Center for Bioenergy and Photosynthesis. Sadly, the prognosis is not great:
...[I]t looks like a nice artistic expression of an artificial leaf, and while it may possibly be true that silk proteins stabilize chloroplast function somehow, proteins in a cell are in a constant state of turnover (some more than others) and eventually (on the scale of hours or perhaps days), the system will inactivate. In isolated chloroplasts spread out on silk, no new nuclear-encoded proteins can be accessed. And as most of the proteins in the chloroplast need to be imported, the life of an isolated chloroplast is necessarily short-lived. So, it won’t be surviving long enough to be useful for a space mission, I’m afraid.
Or even, it seems, for the facades of skyscrapers. Guess we'll have to settle for Lackner and his plastic trees. Or, you know, actual plants.