The excruciating irritation of going through airport security could one day be as pleasant as walking through a garden. A genetically engineered garden, perhaps, but a garden nonetheless.
Plants are being increasingly seen as having the potential to replace sensors and electronic devices, which sounds completely insane at first brush.
June Medford, a pioneering synthetic biologist, says it's time to start harnessing plants' natural sensing abilities and pair them with with the power of genes in other organisms. This will allow us to churn out bomb- and drug-detecting ficus plants, pollution detecting (and fighting) ferns, and the like, she claims.
"The way we screen airports to get on a plane is, everyone goes through detector systems and it's slow. What would make much more sense, my vision is that you would walk through a garden-like setting, with a webcam looking down on plants, seeing if they detected anything," Medford told me in a phone interview.
When engineering living organisms, Once you understand the rules, it's like anything else
"You wouldn't be able to identify an individual, but if you go through 10 people at a time, well, if it detects something you can look through those people in detail," she added.
For years now, Medford, a researcher at Colorado State University who worked one of DARPA's first forays into the field back in 2003, has been reprogramming plants in her lab to serve as these "sentinels."
She's already engineered a plant genus known as arabidopsis to change color when it detects TNT or certain pollutants (plants' natural sensors can be more than 100 times as sensitive as a dog's). Others have been working on engineering plants that tell farmers when they're infected with certain pathogens.
She says that's just the beginning.
Image: Phytodetectors Inc.
"With electronics, we know the path that we went from Turing's computers to a calculator, to the iPhone. We took standardized parts that were standard and predictable, and we improved them and mass produced them," she said. "That's the kind of thing we're now doing with living organisms. Once you understand the rules, it's like anything else."
What is a genetic code, she says, other than a set of instructions, or a case to put new components in? With new genome editing techniques such as CRISPR, engineering a plant (or anything else, really) to do exactly what you want it to is easier than ever.
"Just as integrated circuits can be reused in diverse electronic devices, form cell phones to aircraft, synthetic biology components [genes] should function predictably in different synthetic circuits and plants," Medford and her colleague, Ashok Prasad, wrote in a new paper published in Science.
Medford's TNT-detecting plants. Image: PLOS One
While controversy still surrounds genetically modified organisms used for food, Medford says that soon, the environmental case for sentinel plants will make them a necessity.
The materials used in today's electronics and sensors are mined from the Earth and are most often powered by fossil fuels, which she sees as a huge waste, and potentially unsustainable. Growing a new plant sentinel, meanwhile, simply requires planting new seeds.
"I think we can literally start doing it this decade, and we should start doing it aggressively," she said. "We need to come up with new ways of sensing so that we're saving our environment instead of destroying it."
Engineered plants could be hooked up to electronic and internet-connected systems—a webcam can be rigged to detect color changes in her plants before they're perceptible to the human eye, and can set off an alarm, much like how a metal detector would.
Though she says we can be doing this en masse within five years, there are, of course lots of hurdles to still clear. While CRISPR genome editing is a fairly well-understood practice at this point, there's still a lot of trial and error involved with engineering plants to do exactly what you want them to do.
Then, there are the people who think doing this is just nutty.
"I'm the only one here crazy enough to work with plants. Plants are harder and slower [than working with bacteria]," she said. "Just like anything, it's research. You take two steps forward, one step back. You're kind of feeling your way through the dark."