Green Sapper
Spinach was taught to look for explosives
Julia Korowski, XX2 century, based on the materials of the Massachusetts Institute of Technology: Nanobionic spinach plants can detect explosives
Scientists at the Massachusetts Institute of Technology have taught spinach to find explosives and notify about it by email. The new development is an example of bionics, a combination of biology and technology. The results of the work are published in the journal Nature Materials (Wong et al., Nitroaromatic detection and infrared communication from wild-type plants using plant nanobionics).
The plants created by the researchers recognize nitroaromatic compounds that are often used in the production of mines and explosives. When these substances enter the groundwater, the carbon nanotubes embedded in the leaves emit a fluorescent signal that can be "read" using an infrared camera. A pocket computer connected to it sends an email alert.
Two years ago, MIT Professor Michael Strano and his colleagues taught the Arabidopsis thaliana to recognize nitric oxide using nanoparticles. Strano claims that plants are ideally adapted to monitoring the environment, since they naturally collect information about the external environment.
"Plants are very good analytical chemists," he says. "They have an extensive root system, constantly take samples of groundwater and are able to transport this moisture up to the leaves on their own." In the course of previous research, scientists have developed carbon nanotubes that register hydrogen peroxide, trinitrotoluene (TNT), sarin nerve gas and other chemical compounds. When a targeted molecule binds to a polymer on the surface of such a nanotube, the tube changes the fluorescence intensity.
In a new study, Strano and his colleagues implanted special carbon nanotubes – sensors of nitroaromatic compounds - into spinach leaves. They were placed in the mesophyll of the leaf – the main tissue between the upper and lower layers of the epidermis, where the cells synthesizing chlorophyll are located. When a plant absorbs targeted molecules from groundwater, sensors emit a fluorescent signal. The second type of carbon nanotubes implanted in the tissue fluoresces regardless of the presence of explosives. By comparing the signals, it is possible to understand whether the sensor has registered nitroaromatic compounds. The transfer of targeted molecules to the leaves takes about ten minutes.
To read the signal, you need to direct a laser beam at the sheet – then the nanotubes re-emit light in the near infrared range. It can be registered using a small infrared camera connected to a Raspberry Pi handheld computer or using a smartphone from which the IR filter has been removed.
Scientists have also created spinach, which reacts to dopamine – this hormone affects the growth of roots. Now they are working on creating new sensors that could register the compounds that plants use to transmit information inside tissues. "Plants are very sensitive to environmental changes. They know that the drought is beginning long before us. They can register small changes in soil properties and soil moisture potential. If we get access to these signaling pathways, we will get a huge amount of information," Strano says.
Bionics is the applied science of applying the principles of organization, properties, functions and structures of wildlife in technical devices and systems. Bionics explains what common features and differences exist in nature and technology. There are biological bionics, theoretical bionics and technical bionics. Bionics is closely related to biology, physics, chemistry, cybernetics and engineering sciences.
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03.11.2016