With the byline of “nanobionic plants might one day replace some electrical lighting”, MIT scientists had taken the first step towards truly ‘organic’ lighting. To that end, a group of researchers led by postdoc Seon-Yeong Kwak has successfully embedded particular types of nanoparticles into the leaves of a watercress plant. This experiment resulted in what can be termed as a glowing plant that was able to give off its dim light for a period of around four hours. In essence, the team is looking forth to a future where such plants can be just bright enough to function as low-intensity indoor lights or even dedicated street lights (via specialized nanobionic trees).
Michael Strano, a professor of Chemical Engineering at MIT, and one of the senior authors 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. Plants can self-repair, they have their own energy, and they are already adapted to the outdoor environment. We think this is an idea whose time has come. It’s a perfect problem for plant nanobionics.
As for the core technology in question here, the researchers made use of luciferase, the enzyme that is responsible for the biological glow of fireflies. The organic process entails the reaction of luciferase on a molecule called luciferin, which causes it to emit light. The researchers additionally used the third component in the form of a molecule called co-enzyme A that smooths out the aforementioned process by removing a reaction byproduct that can impede the luciferase.
However, beyond just these core components, the scientists had to devise specific nanoparticle carriers that were suitable for the task at hand and also safe to use (in accordance with FDA). In that regard, they opted for 10 nanometers diameter silica nanoparticles to carry the luciferase, while choosing relatively larger particles of the polymers PLGA and chitosan for luciferin and coenzyme A, respectively. For the induction part, these nanoparticle carriers (with their specific content) were suspended in a solution, and the plant leaves were immersed in the very same solution. A lab-made high-pressure environment allowed the particles to invade the leaves through tiny pores known as stomata.
According to MIT News, the glowing process was then achieved by as follows –
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.
Now in the realm of practicality, the researchers produced a nanobionic-powered glow that is about one-thousandth of the magnitude needed to read by. However, on the brighter side (excuse the pun), they were able to lengthen the time of the glow from just 45 minutes to beyond 3.5 hours. Furthermore, they are also fairly confident that the magnitude of the light can be enhanced by tinkering with the concentration and release rates of the enzyme components.
Interestingly enough, the scientists are looking at the possibility of spray-painting the nanoparticles directly onto the plant surfaces for rapid transformation of trees and shrubs into lighting mechanisms. Moreover, they are also considering the ‘off’ switch for such organic glowing plants, by introducing nanoparticles that would house the luciferase inhibitor. Strano added –
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.
Source: MIT News