Streetlights could be replaced by glow-in-the-dark trees
Roads of the future could be lit by glowing trees instead of streetlamps, thanks to a breakthrough in creating bioluminescent plants.
Experts injected specialised nanoparticles into the leaves of a watercress plant, which caused it to give off a dim light for nearly four hours.
The chemical involved, which produced enough light to read a book by, is the same as is used by fireflies to create their characteristic shine.
To create their glowing plants, engineers from the Massachusetts Institute of Technology (MIT) turned to an enzyme called luciferase.
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 components into a different type of nanoparticle carrier.
The nanoparticles help them to get to the right part of the plant and also prevent them from building to concentrations that could be toxic to the plants.
The result was a watercress plant that functioned like a desk lamp.
Researchers believe with further tweaking, the technology could also be used to provide lights bright enough to illuminate a workspace or even an entire street, as well as low-intensity indoor lighting.
Michael Strano, professor of chemical engineering at MIT and the senior author of the study, said: ‘ 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.’
‘ Our work very seriously opens up the doorway to streetlamps that are nothing but treated trees, and to indirect lighting around homes.’
Luciferases make up a class of oxidative enzymes found in several species that enable them to ‘ bioluminesce’, or emit light. Fireflies are able to emit light via a chemical reaction in which luciferin is converted to oxyluciferin by the luciferase enzyme.
Some of the energy released by this reaction is in the form of light.
The reaction is highly efficient, meaning nearly all the energy put into the reaction is rapidly converted to light.
Lighting accounts for around 20 per cent of worldwide energy consumption, so replacing them with naturally bioluminescent plants would represent a significant cut to CO2 emissions.
The researchers’ early efforts at the start of the project yielded plants that could glow for about 45 minutes, which they have since improved to 3.5 hours.
The light generated by one ten centimetre ( four inch) watercress seedling is currently about one-thousandth of the amount needed to properly read by, but it was enough to illuminate the words on a page of John Milton’s Paradise Lost. The MIT team believes it can boost the light emitted, as well as the duration of light, by further optimising the concentration and release rates of the chemical components.
For future versions of this technology, the team hopes to develop a way to paint or spray the nanoparticles onto plant leaves, which could make it possible to transform trees and other large plants into light sources.