MIT researchers turn spinach plants into explosive detectors

spinach explosive detection
© Christine Daniloff/MIT

A new field of study called plant nanobionics looks to engineer electronic systems into plants for monitoring and detecting substances in the world around them. It seems strange, but could be a valuable tool for discovering pollution and other dangerous chemicals in the environment.

Researchers at MIT have recently demonstrated that spinach plants can be made into explosive detectors. The leaves were embedded with carbon nanotubes and the plant is able to wirelessly communicate with a smartphone or Raspberry Pi.

The plant was designed to detect nitroaromatics, which are compounds that are used in landmines and other explosives, present in the groundwater. If any substances are present, the plant emits a fluorescent signal that can be read by an infrared camera connected to a Raspberry Pi or similar microcomputer, which then emails an alert the user. A smartphone alone can also be adapted to read the infrared signal and send the email alert.

Plants could also be designed to detect other pollutants and harmful chemicals like nitric oxide from combustion, TNT and the nerve gas sarin and even warn of harsh environmental conditions like drought, becoming an essential source of information about the health and safety of our world. Another possibility is that plants could become an important tool in maximizing agriculture yields.

“This is a novel demonstration of how we have overcome the plant/human communication barrier,” said Michael Strano, the Carbon P. Dubbs Professor of Chemical Engineering at MIT.

“Plants are very good analytical chemists. They have an extensive root network in the soil, are constantly sampling groundwater, and have a way to self-power the transport of that water up into the leaves.”

The researchers added the explosive-detecting nanotubes by applying a solution to the underside of the leaf which infused the nanotubes in the layer of the leaf where most photosynthesis takes place. Any nitroaromatics in the groundwater will be drawn into the plant and detected by the nanotubes in 10 minutes.

A light shone on the leaves prompts the nanotubes to emit near-infrared fluorescent light that can then be picked up by an infrared camera or a modified smartphone that has has the infrared filter removed. Currently the change in fluorescence can be detected within a distance of one meter, but the team is working to increase that distance.

MIT researchers turn spinach plants into explosive detectors
Plants could be the ultimate environmental sensors.

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