A 2016 study about scientists receiving alerts from spinach went viral this week, bringing fresh attention to the emerging field of plant nanobionics—and sparking plenty of jokes about getting email from your leafy greens. In the study published in the journal Nature Materials, MIT researchers explained that they had implanted into the leaves of spinach plants carbon nanotubes capable of detecting when the roots had encountered the nitro-aromatic compounds often found in explosives. Light emitted by the nanotubes—which are too small to be seen by the human eye—could then be picked up by infrared cameras, which would trigger an email alert to scientists. Study co-author Michael Strano in 2016 told the BBC that the study was a proof of concept that "outlines how one could engineer plants like this to detect virtually anything."
"Plants are very good analytical chemists," said Strano, per euronews. "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." In later research, Strano and fellow researchers used the technology to detect arsenic. He tells Fast Company that "sensor plants"—not designed to be eaten—could help farmers better develop plants that can withstand the impact of climate change. They could also clue farmers in on issues—from insects to heat—long before they could be spotted with the naked eye. "The plant has that information days, sometimes weeks, in advance. The plant is a very sensitive environmental sensor, and this technology allows us to intercept it so humans can intervene." (Read more spinach stories.)