In case you’re going by your day and feel like normal reading lamps just don’t cut it anymore, then you’re in luck! In an experiment funded by U.S. Department of Energy, engineers at MIT have created plants that glow in the dark. What they actually did was embed specialized nanoparticles into the leaves of the watercress plant, which made it to emit a dim light for nearly upto 4 hours.
Michael Strano, a Professor of Chemical Engineering at MIT 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.”
The enzyme they used is called luciferase and it’s the same enzyme that gives fireflies their glow. What luciferase does is that it reacts with a molecule called luciferin, emitting light as a byproduct of their reaction. There is another byproduct of this reaction that can affect the activity of luciferase and to combat that, a molecule dubbed co-enzyme A is used.
It doesn’t end here, however, all the three components have to be mixed in the right amount, otherwise they may be toxic to the plants. Another thing that had to be taken care of was the nanoparticle itself, which happened to be compliant to the regulations set by U.S. Food and Drug Administration and was “generally regarded as safe”.
They used different nanoparticles for each chemical. For luciferase, they used Silica nanoparticles with a diameter of about 10 nanometers. For luciferin and co-enzyme A, they used slightly larger PLGA and chitosan respectively. To get the particles in the plants, they first suspended the nanoparticles in a solution and later immersed the plants in that solution while being subjected to high pressure. The high pressure allowed the nanoparticles to enter the leaved through tiny pores called the stomata.
During the earlier experiments, the engineers could only manage a glow of 45 minutes. But it has, since then, been perfected to 4 hours. The intensity of the light is another challenge to say the least. As of now the light generated by one watercress seedling is equivalent to about one-thousandth the amount needed to read comfortably, which is too low to be usable. However, the engineers believe that by further optimizing the concentrations of components, they can increase both the duration and intensity of light even further.
It has also been demonstrated by researchers that the glow can be turned on or off, just like in a lamp. How is this possible? Well, by increasing the amount of the aforementioned byproduct that inhibits luciferase. This can help control the lights vis external environmental conditions like the intensity of sunlight.
There have been previous attempts of this very same experiment, but they involved genetically engineering the plant itself to express the gene for luciferase. This process, however was too complicated and the light yielded was too dim. It was also only applicable to tobacco and Arabidopsis thaliana. Strano’s experiment could be performed on any type of plant and was tested on arugula, kale, spinach and watercress.
Engineers are trying to make the process much easier by spraying, the nanoparticles directly on the leaves like a paint. That was, it will be possible to do this on a large scale like turning trees into street lamps.
Strano further says, “Our target is to perform one treatment when the plant is a seedling or a mature plant and have it last for the lifetime of the plant. Our work very seriously opens up the doorway to streetlamps that are nothing but treated trees, and to indirect lighting around homes.”
Lighting accounts for 20% of the world’s energy consumption and with this discovery, it is evident that glowing plants may be the future given that it is perfected in time and is feasible both environmentally and financially. “Plants can self-repair, they have their own energy, and they are already adapted to the outdoor environment,” says Strano.
Bioengineering has definitely come a long way. The feats, once considered impossible are now becoming norms. Who would’ve thought that one day plants would replace electrical lighting altogether. Although, we haven’t been there yet, far from it in fact. But considering the rate of improvement, it might not be long when it might actually happen.