A new direction in science: plant nanobionics
Nanotechnology has improved the ability of plants to photosynthesis
A group of scientists from the Massachusetts Institute of Technology has expanded the abilities of plants by introducing carbon nanotubes into their chloroplasts. After the modification, the ability to photosynthesis increased by 30% in plants, and sensitivity to gases polluting the environment also appeared.
The role of plants in the life of the planet and its inhabitants is enormous: they are able to create organic substances from inorganic ones, serve as a source of oxygen that animals and people breathe, and are also rich in nutrients. A group of researchers from the Massachusetts Institute of Technology figured out how to make plants even more functional and used modern techniques in the field of nanotechnology for this.
As reported in an article published in the journal Nature Materials (Giraldo et al., Plant nanobionics approach to augment photosynthesis and biochemical sensing – VM.), the ability of plants to photosynthesis increased by 30% after the introduction of carbon nanotubes into chloroplasts – organelles, where the actual process of capturing light energy and the formation of organic substances and water takes place. The use of a different type of carbon nanotubes has led to the creation of plants sensitive to nitrogen oxide.
The scientists attributed their research to a new field, which they called "plant nanobionics".
"Plants are a very promising technological platform. They are capable of self–healing, environmentally stable, resistant to aggressive environmental conditions and are able to provide themselves with water and nutrition," says the lead author of the study, Michael Strano.
Initially, the idea of nanobionic plants came out of a project to create self-healing solar cells that would regenerate like plant cells. As part of this work, the researchers tried to increase the ability of chloroplasts to photosynthesis, which could be used in solar panels.
As you know, chloroplasts have everything necessary for two-stage photosynthesis. First, the pigment chlorophyll absorbs light. Light quanta excite electrons passing through the thylakoid membranes of the chloroplast. Then the plant uses the received electricity to carry out the second stage of photosynthesis – the creation of sugars.
Even if chloroplasts are removed from plants, they will still not lose their ability to photosynthesize, but after a few hours they will begin to break down, because light and oxygen damage photosynthetic proteins. If plants are able to repair these damages, then autonomous chloroplasts cannot do this.
To prolong the performance of chloroplasts, scientists implanted cerium oxide nanoparticles, also known as nanocerium, into them. These particles are strong antioxidants, that is, they prevent oxidative processes by "neutralizing" oxygen-containing radicals and other highly reactive molecules. In this way, chloroplasts are protected from damage.
To deliver nanoparticles to chloroplasts, a separate technique was developed, which scientists called the abbreviation LEEP: the particles are packed in polyacrylic acid, as if in an envelope, due to which they acquire the ability to penetrate the hydrophobic lipid membranes that surround chloroplasts.
Using the same technique, the researchers introduced semiconductor carbon nanotubes coated with negatively charged DNA into chloroplasts. Plants usually use only 10% of sunlight, but nanotubes acted as antennas that allowed plants to cover new wavelengths of light – for example, ultraviolet, green and near infrared ranges.
As the results of the experiment showed, after the introduction of nanotubes, photosynthetic activity, measured by the electron flow rate through thylakoid membranes, increased by 49% compared to conventional isolated chloroplasts.
What is even more interesting, when nanocerium and carbon nanotubes were implanted into chloroplasts simultaneously, the latter remained active for several additional hours.
In the course of a subsequent experiment, Strano and his colleagues took a live plant – the rhesus Thaliana (Arabidopsis thaliana), and tried to implant the same nanoparticles into it, only using a different technology. A solution of nanoparticles was applied to the underside of the plant leaf, and it penetrated into the leaf through tiny pores that usually allow carbon dioxide to pass inside and release oxygen.
Photo from the MIT Bionic plants press release - VM.)
This time, the nanotubes that moved directly into the chloroplasts of the Thal's rhesus increased the photosynthetic flow of electrons by 30%.
"We are still looking for an answer to the question of how exactly nanoparticles affected the production of chemical fuels, for example, glucose," says study co–author Juan Pablo Giraldo, also from MIT.
Based on the results of their work, the scientists wondered how wide the scope of this innovation could be: plants could potentially be turned into photonic devices with an autonomous power source, and used as detectors of explosives or chemicals. In addition, it is possible to develop a method of introducing electronics into the plants themselves.
Strano and his colleagues specialize in creating carbon nanotube sensors for various chemicals, including hydrogen peroxide, explosives and sarin nerve gas. When the target molecule binds to the polymer covering the nanotube, the fluorescence of the latter changes - this is how the substance is detected.
Researchers have shown by the example of the same Tal's rhesus that plants can serve not only as improved "solar panels", but also as chemical sensors. It is only necessary to introduce carbon nanotubes into their chloroplasts that are sensitive to nitrogen oxide, an environmental pollutant that is synthesized during gorenje.
Scientists also plan to create plants sensitive to pesticides, fungal infections and bacterial toxins in order to ensure the safety of humans and animals through these biosensors in the future. Moreover, Strano and his colleagues are working on a project to implant electronic nanomaterials, such as graphene, into plants. Thus, it will be possible to create an entire ecosystem that monitors the level of cleanliness and safety of the environment, the inventors believe.
Portal "Eternal youth" http://vechnayamolodost.ru18.03.2014