Glow-in-the-dark plants hold promise as future lighting source

December 27, 2017 // By Rich Pell
Engineers at MIT (Cambridge, MA) have created "nanobionic" light-emitting plants that hold promise as self-powered and self-repairing sources of illumination.

The engineers embedded nanoparticles into the leaves of watercress plants, which caused the plants to give off dim light for nearly four hours. With further optimization, say the researchers, such plants may one day be able to provide low-intensity indoor lighting, or transform trees into self-powered streetlights.

"The vision is to make a plant that will function as a desk lamp - a lamp that you don’t have to plug in," says Michael Strano, the Carbon P. Dubbs Professor of Chemical Engineering at MIT and the senior author of a study on the project. "The light is ultimately powered by the energy metabolism of the plant itself."

The goal of the researchers is to use plant nanobionics - embedding plants with different types of nanoparticles - to engineer plants that can take over many of the functions now performed by electrical devices. Having previously designed plants that can detect explosives and communicate that information to a smartphone, as well as plants that can monitor drought conditions, the researchers turned their attention to lighting, which accounts for about 20% of worldwide energy consumption.

"Plants can self-repair, they have their own energy, and they are already adapted to the outdoor environment," says Strano. "We think this is an idea whose time has come. It's a perfect problem for plant nanobionics."

In this case, the researchers packaged an enzyme called luciferase - the same enzyme that enables fireflies to glow - and two enabling molecules called luciferin and co-enzyme A, each into a different type of nanoparticle carrier. The nanoparticles help each component get to the right part of the plant, as well as prevent them from reaching concentrations that could be toxic to the plants.

Silica nanoparticles about 10 nanometers in diameter were used to carry the luciferase, while slightly larger particles of the polymers PLGA and chitosan were used to carry luciferin and coenzyme A, respectively. To get the particles into