Bacteria can be genetically engineered to become onboard sensors.
Image: iGEM Team
Drones—especially autonomous ones—can sometimes creep people out because it seems like they have minds of their own. But a new, NASA-backed research project seeks to create something quite different: A living, breathing, biodegradable drone made out of bacteria and fungi.
The immediately clear advantage is an environmental one: Drones crash all the time and are often unsalvageable, adding plenty of plastic and other trash to the wealth of it we already have. But, long term, biomaterials aren't the most interesting draw here.
Drones are useful because of all the sensors they have on them—ones that can detect pollution, air quality, bombs, movement, and lots of other things on them. But those sensors use up a ton of power and are often pretty heavy, leading to short flight times. Bacteria, algae, and other living things, however, can be engineered to sense many of the things that electronic sensors do, all while weighing essentially nothing and taking up absolutely no electrical power.
"A major limitation of current research with UAVs is the size and high power consumption of analytical instruments, which require bulky electrical components and large fuselages to support their weight," the group wrote on its project page. "By moving these functions into cells with biosensing capabilities—for example, a series of cells engineered to report GFP, green fluorescent protein, when conditions exceed a certain threshold concentration of a compound of interest, enabling their detection post-flight—these problems of scale can be avoided."
It sounds kind of crazy, and the work is still in its infancy, but it's not an unprecedented idea. Synthetic biologists are working on bioengineering plants that can detect bombs for airport security purposes, and there's no reason that technology like that can't be built into a drone from the drone's infancy.
But back to the building of the drone itself: The team, which is mostly made up of Stanford and Brown University students but also includes several NASA Ames scientists, says it can make a drone out of mycelium, the vegetative part of fungi that can be molded into a foam-like structure. The mycelium is protected by sheets of bacteria-grown cellulose, which help resist water. Circuits are printed with silver ink that are relatively biodegradable.
In theory, if these drones crash, you can just leave them there and they'll break down naturally.
What are these biodrones going to be used for? Well, they might be used to look for life in the upper atmosphere, where it's quite tough for us to look for microbial life. They can also be used to do whatever normal drones do, whether it be search and rescue, environmental monitoring, or other aerial sensing.
Obviously, normal drones perform a lot of these functions just fine, so the real added value here would be the synthetic biology component. That aspect isn't terribly easy to pull off: Bioengineered organisms are great in the laboratory, perhaps a little less predictable when you put them on a drone.
"Housing live cells on an aerial system presents a new set of problems, chief amongst which is the concern of horizontal gene transfer," the team wrote. That means that bacteria can start passing genes between one another, quickly evolving into something other than what it was designed for. Then there's the question of what happens when a bunch of genetically engineered bacteria crash into a forest or something:
"We must take steps to protect the environment from our cells and avoid the possibility that our engineered genes proliferate throughout ecosystems," the team wrote. "We must address what might happen if our biological UAV were to crash and allow the cells on its biofilm to act as an invasive species."
In any case, this is crazy, forward-looking stuff.