MIT engineers induce plants to give off light

New York: Engineers at Massachusetts Institute of Technology (MIT) have found a way to induce plants to give off dim light, a major step towards realising their vision of using plants to illuminate the workspace.

"The vision is to make a plant that will function as a desk lamp -- a lamp that you don't have to plug in. The light is ultimately powered by the energy metabolism of the plant itself," said Michael Strano, Professor at MIT and the senior author of the study.

By embedding specialised nanoparticles into the leaves of a watercress plant, the researchers successfully induced the plants to give off dim light for nearly four hours, according to the study published in the journal Nano Letters.

This technology could also be used to provide low-intensity indoor lighting, or to transform trees into self-powered streetlights, the researchers said.

To create their glowing plants, the MIT team turned to luciferase, the enzyme that gives fireflies their glow. 

Luciferase acts on a molecule called luciferin, causing it to emit light. Another molecule called co-enzyme A helps the process along by removing a reaction byproduct that can inhibit luciferase activity.

The MIT team packaged each of these three components into a different type of nanoparticle carrier. 

To get the particles into plant leaves, the researchers first suspended the particles in a solution. 

Plants were immersed in the solution and then exposed to high pressure, allowing the particles to enter the leaves through tiny pores called stomata.

Particles releasing luciferin and coenzyme A were designed to accumulate in the extracellular space of the mesophyll, an inner layer of the leaf, while the smaller particles carrying luciferase enter the cells that make up the mesophyll. 

The particle carriers gradually release luciferin, which then enters the plant cells, where luciferase performs the chemical reaction that makes luciferin glow, the study said.