Experts at the Massachusetts Institute of Technology (MIT), US have created plants that glow by embedding specialised nanoparticles into their leaves. The researchers said that this technology could also be used to provide low- intensity indoor lighting, paving the way for trees to replace streetlights.To create the glowing plants, the scientists used luciferase, the enzyme that gives fireflies their glow. Luciferase acts on a molecule called luciferin, causing it to emit light. Another molecule called coenzyme A helps the process along by removing a reaction byproduct that can inhibit luciferase activity.
The researchers combined the three components to create a different type of nanoparticle carrier. The nanoparticles help each component get to the right part of the plant. They also prevent the components from reaching concentrations that could be toxic to the plants. The result was a watercress plant that functioned like a desk lamp.
To get the particles into plant leaves, the researchers first suspended the particles in a solution and then exposed the plants to high pressure, allowing the particles to enter the leaves.
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 PLGA particles gradually release luciferin, which then enters the plant cells, where luciferase performs the chemical reaction that makes luciferin glow.
The researcher’s early efforts yielded plants that could glow for about 45 minutes, which they have since improved to 3.5 hours. The light generated by one 10-centimetre watercress seedling is currently about one-thousandth of the amount needed to read by. However, the researchers believe they can boost the light emitted, as well as the duration of light, by further optimising the concentration and release rates of the components.