Imagine that instead of turning on a lamp when it gets dark, you could read exclusively by the light of a bright plant. This is what a team of engineers from the Massachusetts Institute of Technology (MIT) has achieved: taking the first step to make this vision a reality.
To create these glow-in-the-dark plants, as if we were immersed in James Cameron’s Avatar universe , scientists incorporated specialized nanoparticles into the leaves of a watercress plant, inducing the plants to emit dim light for nearly four hours.
Experts believe that, with further optimization, such plants will one day be bright enough to illuminate a workspace.
“The idea is to make a plant that works like a desk lamp, a lamp that does not have to be plugged in. The light is ultimately driven by the energy metabolism of the plant,” says Michael Strano, leader of the study that publishes the journal Nano Letters. .
This technology could also be used to provide low-intensity indoor lighting, or to transform trees into self-contained streetlights , the authors argue.
Nanobionic plants
What they do is provide plants with novel characteristics by introducing different types of nanoparticles. The team’s goal is to design plants to handle many of the functions that electrical devices now perform.
Lighting, which accounts for about 20% of global energy consumption, appears to be the next logical goal. “Plants can self-heal, they have their own energy and they are already adapted to the outside environment. We think this is an idea that has come to the fore. It is a perfect problem for plant nanobionics,” says Strano.
How did they do it?
To create the glowing plants, the MIT team turned to luciferase, the enzyme that gives precious fireflies their glow. Luciferase acts on a molecule called luciferin, which allows it to emit light. Another molecule called coenzyme A helps the process, removing a byproduct of the reaction that can inhibit luciferase activity.
The MIT team packaged each of these three components in a different type of nanoparticle carrier (classified by the FDA as “generally regarded as safe”), which help each component get to the correct part of the plant. They also prevent the components from reaching concentrations that could be toxic to plants.
The researchers used silica nanoparticles about 10 nanometers in diameter to transport luciferase, and used slightly larger particles of the PLGA and chitosan polymers to transport luciferin and coenzyme A, respectively.
To get the particles in plant leaves, they first suspended the particles in a solution. The plants were immersed in this solution and then exposed to high pressure, allowing the particles to enter the leaves through small pores called stomata.
The first experiments produced plants that glowed for about 45 minutes, and since then they have improved up to 3.5 hours. The light generated by a 10 centimeter watercress (Nasturtium officinale ) plant is currently around one thousandth of the amount needed for reading, but the researchers believe they can increase the emitted light, as well as the duration of the light, by further optimizing plus the concentration and release of the components.
For future versions of this technology, the researchers hope to develop a way to paint or spray the nanoparticles on plant leaves, which could allow the transformation of trees and other large plants into light sources.
Referencia: Seon-Yeong Kwak et al. A Nanobionic Light-Emitting Plant, Nano Letters (2017). DOI: 10.1021/acs.nanolett.7b04369
