Leafy greens are not everyone’s favorite. Take spinach for example. Lots of kids and even some adults turn up their noses, as soon as they see it on their plate. It’s best to trust in spinach, however. Not only is it a superfood, as Popeye cartoons have clearly demonstrated, but it can be a superhero, when imbued with sensors to detect explosives.
MIT engineers recently accomplished this, allowing a spinach plant to send an email to a smartphone when it encountered nitroaromatics—chemical compounds found in many types of explosives. The plants roots picked up this compound, which was sent to the leaves, where nanotube sensors triggered a signal.
Two sets of nanocarbon tubes were used. MIT scientists employed a technique known as vascular infusion to place them into the underbelly of the plant’s leaves, within a layer known as the mesophyll—where photosynthesis takes place. One set of nanotubes sent out a constant fluorescent signal. This gave the computer monitoring it a baseline. The other sent a signal when it encountered the target molecule. This makes it easier for the computer to differentiate between the plants normal state and chemical detection.
After encountering the explosive compound at its roots, it took approximately 10 minutes to reach the leaves. Once detection took place, nanotubes send out a wireless fluorescent signal, picked up by an infrared camera. That camera relayed the message to an attached computer, about the size of a smartphone that sent an email alert. The monitoring system works for up to a meter away. Now researchers are working out increasing its range.