‘Bionic spinach’ can be used to detect bombs

Long known to be a good source of iron and other vitamins and minerals, spinach is believed to lead to stronger muscles, improved eyesight, and healthy blood pressure – and in the right hands, it can be used as a bomb detector, according to a new Nature Materials study.

As BBC News and the Daily Mail are reporting, researchers from the Massachusetts Institute of Technology (MIT) implanted tiny tubes into the leaves of spinach plants which enabled them to pick up nitro-aromatics – chemicals which are found in landmines and buried explosives.

Specifically, they embedded nanoparticles and carbon nanotubes into the leaves. As the plants gather groundwater, scientists can tell in real time if it contains any nitro-aromatics. Shining a laser onto the leaves causes the implanted nanotubes to give off near-infrared fluorescent light, which can be detected wirelessly by a special camera outfitted to a handheld device.

That device, which can either be an inexpensive Raspberry Pi computer or a smartphone which has had its infrared filter removed, then generates an email to the user to notify him or her about the chemical levels detected in the groundwater. Study co-author professor Michael Strano said that the work was an important proof-of-concept that could lead to bigger, better things.

‘Plant nanobionics’ can be used to predict drought, detect pollutants

In a statement, he called the new study “a novel demonstration of how we have overcome the plant/human communication barrier,” noting that plants could be altered to warn about drought conditions or pollutants. In fact, as Strano told BBC News, “our paper outlines how one could engineer plants like this to detect virtually anything.”

Previously, the professor’s lab successfully demonstrated how carbon nanotubes could be used as sensors to detect TNT, hydrogen peroxide, and even sarin nerve gas. They do so by changing the way they glow when exposed to a specific target molecule, demonstrating a new approach to engineering which the MIT researchers have dubbed “plant nanobionics.”

“The plants could be used for defense applications, but also to monitor public spaces for terrorism-related activities, since we show both water and airborne detection. Such plants could be used to monitor groundwater seepage from buried munitions or waste that contains nitro-aromatics,” the professor told BBC News.

With their current set-up, his team said that they can detect signals from the plant at a distance of about one meter, but noted that they are working to expand that distance. Furthermore, they think that the approach could also be adapted to engineer other types of sensors, or even to create other types of bionic plants, including those that could change colors or pick up radio signals.

“Plants are very environmentally responsive. They know that there is going to be a drought long before we do. They can detect small changes in the properties of soil and water potential,” Strano explained. “If we tap into those chemical signaling pathways, there is a wealth of information to access.”

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Image credit: Christine Daniloff/MIT