[MUSIC PLAYING] Imagine if a plant could
detect harmful chemical compounds, such as explosive
material found in ground water. And then imagine
that that same plant could relay that information
quickly and directly to a user. Well, believe it or
not, a team of MIT engineers has shown this
plant-to-human communication is a lot closer
than one may think. To demonstrate this
process, the team first embedded
carbon nanotubes that can detect nitroaromatic
compounds, which are often used in land mines
and other explosives, into the leaves
of spinach plants. These carbon nanotubes
emit a fluorescent signal that can be read with
an infrared camera. Some of the embedded
carbon nanotubes emit a constant
fluorescent signal that serves as a reference,
while the others emit a fluorescent signal when an
explosive compound is detected. Having both makes it
easier to determine if the explosive sensor has
detected anything or not. They then introduced
the explosive compounds to the plant’s roots. Similar to how a
plant would naturally sample from the
ground water, if there are any explosive molecules,
it takes about 10 minutes for the plant to draw them up
into the leaves, where they first encounter the nanotubes. To read the signal,
the researchers shine a laser on to
the leaf, prompting the embedded nanotubes to
emit near infrared fluorescent light. This light can then be detected
with a cheap infrared camera connected to a Raspberry
Pi, which is a credit card sized computer,
similar to the computer inside your average smartphone. Then, that tiny computer
sends an email to the user, alerting them of this detection. In addition to
detecting pollutants, the researchers are working
to employ this technology to sense environmental
conditions, such as drought, or to
monitor plant health.