Imagine that when it is dark, you can read through the glowing plants on your desk instead of turning on a light. What kind of experience is this?
Massachusetts Institute of Technology (MIT) engineers have taken a critical first step in the process of realizing this vision. Engineers implanted special nanoparticles into the leaves of watercress, which induced the watercress to glow for nearly four hours. They believe that through further optimization, this luminous plant will one day be enough to illuminate a work space.
Michael Strano, a professor of chemical engineering at MIT and the senior author of the study, said that their idea is to create a plant that can be used as a desk lamp—the power does not need to be turned on, and the light source ultimately comes from the crop itself. Energy Metabolism.
The researcher said that this technology can also be used to provide low-intensity indoor lighting, or to turn trees into self-supplied circuit lights.
Strano said that lighting accounts for about 20% of global energy consumption, and plants can repair themselves, have their own energy, and have adapted to the external environment. They believe that the time is ripe.
A new research field created by the Strano laboratory is called Plant nanobionics, which aims to impart new characteristics to plants by implanting different types of nanoparticles into plants. The team's goal is to transform plants to replace many of the functions provided by electrical installations. Previously, researchers have designed plants that can detect explosives and transmit information to smartphones, as well as plants that can monitor drought conditions.
It is reported that luciferase is an enzyme that makes fireflies glow. In order to make light-emitting plants, the MIT team turned to this enzyme. Luciferase acts on a molecule called luciferin, which can make luciferin emit light. Another molecule called co-enzyme A (co-enzyme A) can help achieve the process of luminescence by removing the by-products of the reaction that can inhibit the activity of luciferase.
The research team packaged these three components in different types of nanoparticle carriers. These nanoparticles are all made of materials that the U.S. Food and Drug Administration classifies as "generally considered safe" to help each ingredient reach the right part of the plant. Nanoparticles can also prevent these components from reaching concentrations that may produce toxins to plants.
The researchers used silica nanoparticles with a diameter of about 10 nanometers to carry luciferase, and then used slightly larger polymers PLGA (polymers PLGA) and chitosan particles (chitosan) to carry luciferin and coenzymes, respectively. A. In order to allow these particles to enter plant leaves, the researchers first suspended these particles in a solution, then soaked the plants in the solution, and then exposed them to high pressure to make these particles enter the leaves through tiny pores (stomata).
The particles that release luciferin and coenzyme A accumulate in the extracellular space of the mesophyll (that is, the inner layer of the leaf), while the small particles carrying luciferase enter the cells that make up the mesophyll. After the PLGA particles gradually release luciferin, the luciferin enters the plant cell, and the luciferase chemically reacts in the cell to make the luciferin emit light.
Initially, the plant made by the research team glowed for about 45 minutes. After improvement, the glow time was increased to 3.5 hours. Although a 10 cm watercress seedling produces one-thousandth of the amount of light currently required for reading, the researchers believe that by further optimizing the concentration and release rate of each component, the amount of light can be increased and the light-emitting time can be prolonged.
Previously, the production of light-emitting plants relied on genetically engineered plants, but this was a troublesome process and the light emitted was very weak. Moreover, these studies are all carried out on tobacco and Arabidopsis thaliana, which are often used in plant genetic research. However, the method developed by the MIT research team can be applied to any type of plant. At present, in addition to watercress, they have proven this with arugula, kale and spinach.
In the future, MIT hopes to develop a method to coat or spray nanoparticles on plant leaves to turn trees and other large plants into light sources.
Strano stated that they intend to perform a technical treatment when the plant is a seedling or mature plant, and make it continue to play a role throughout the plant's life cycle.
The research team also demonstrated the addition of nanoparticles carrying fluorescein inhibitors to turn off the light source, which helped them create plants that can turn off the light source according to changes in environmental conditions (such as sunlight).
It is reported that the research has received financial support from the U.S. Department of Energy.
