For scientist Lynn Rothschild of the NASA Ames Research Center — who holds a title that’s the stuff of sci-fi dreams: Astrobiologist — biology has the potential to be the engine of the future for technology, industry, space exploration and even drones.
Lynn heads an ambitious collaborative robotics project that comprises undergraduate students from Stanford, Spelman and Brown University, along with guidance from NASA researchers, to develop what you could call biodrones: fully biodegradable UAVs composed entirely of cellular and organic material. The idea for a biodegradable drone came to Lynn when a NASA colleague lost a research drone in Arctic waters; UAV components don’t easily disintegrate, and the electronics, batteries and metal pose real threats to a delicate ecosystem. The team entered the biodrone as a project in this year’s International Genetics Engineering Machine competition (iGEM), but it also holds promise for real-world, and real-otherworldly, UAV and space exploration applications.
The Biodrone iGEM prototype, put together by Eli Block (Brown University).
First, the drones are built entirely of, and by, cells, making these UAVs 100% biodegradable, a sustainable technology. The drones begin to self-destruct 24 hours after use, at which time the cells are cued by an enzyme to do their best Wicked Witch impression and dissolve into a puddle of sugar water.
For further environmental safeguarding, a mind-boggling process of genetic engineering called codon security* ensures that the cells’ DNA won’t be able to cross-pollinate and enter other environments. This is critically important because many of the cells used to make the drones have amped-up genetic material taken from extremophiles — organisms that thrive in the most extreme conditions on the planet — and when the drones disintegrate you wouldn’t want these synthetic characteristics transferred to other environments.
Finally, bioengineered technology would have the abilities to self-replicate, self-repair, pick up other atoms and run off of energy from carbon dioxide and water. And with the safeguards that they’ve built in, Lynn says that crashing a biodrone would be no more detrimental to the environment than dropping your cotton sweater on the ground.
Autopilot circuits could be made of conductive silver nanoparticle ink. Dr. Kosuke Fujishima in the Ames lab, in conjunction with AgIC, printed this circuit.
As for the drone itself, the body is basically a mushroom, fungal mycelia spores seeded in a mold and then wrapped in a bio-plastic skin of pure cellulose produced by bacteria. This skin is waterproofed by wasps. Student developer Ian Hull recognized that the paper wasp chews up wood and spits out waterproof paper, which the wasps then use to line the outside of their nests. A research team isolated the proteins in the wasps responsible for this waterproofing process, and the UAV team assigned these proteins the task of waterproofing the UAV.
Remarkably, the onboard electronics can also be synthesized. Instead of traditional electronic sensors for gathering and analyzing things like atmospheric data — the presence of toxic gases, for instance — the biodrones have a cell layer with biosensing capabilities. These cells change color when they detect the presence of certain gases. Bafflingly, even the circuitry for an autopilot can theoretically be bioengineered, thanks to the proven conductivity of silver nanoparticle ink.
The team still uses 3D-printed plastic for the propellers, however. And though they haven’t yet settled on battery design, options abound there as well: microbial fuel cells; appropriating the energy generation process from electric eels; or using solar cells to create energy in a process similar to photosynthesis. “Imagine,” Lynn says, “an asparagus battery!” She also reminded me that people biosynthesize electricity all the time in our brains — our neurons and nerve impulses work by turning chemical energy into electric energy — intimating that there’s untapped potential there as well.
Photo courtesy Lynn Rothschild.
Made on Mars
So why has UAV biotechnology attracted the attention of NASA? First, synthetic biology offers many advantages over traditional construction. Notably, it makes for a great carry-on item. When it comes to space travel, weight is especially precious. So what if, instead of loading a rocket down with components or pre-assembled pieces of equipment, you’d only need to pocket a few vials of cells? These cells would then be triggered to replicate, when on Mars**, for instance, and you’d have an industrial agriculture — growing and harvesting your own construction crop. This means that one day drones, and other technology, could be a renewable resource. You could also apply synthetic biology to growing food, fuel, and even to “biomining” bricks (another project of Lynn’s). For Mars, it’d be like an agricultural and industrial revolution all at once.
Drones, made on Mars, could then map Mars. Turns out UAV technology is valuable to NASA for the same reasons it’s become so valuable to folks like farmers and surveyors here on Earth. With ground sensing from rovers like Spirit and Opportunity, you get a lot of detailed information but have a terribly limited coverage area; with satellite imagery you can get a lot of coverage but pretty lousy detail. Drones, operating in the space between the two, can do both and do them well.
Inroads and Wormholes
Here’s the kicker: All of this took Lynn’s team of undergrad students one summer to work out. She speaks of her team glowingly and trusts them with making all the inroads of innovation. She gives all credit for the project’s success to their hard work and ingenuity. Actually, it seemed the team’s biggest hang-up didn’t have anything to do with solving daunting engineering problems, but with confronting social conventions — they were afraid that calling their project a “drone” would connote a military connection, which they were desperate to eschew. Consummate empiricists, they went so far as to conduct a survey to assess public opinion about the term.
In conversation with Lynn it’s quite clear that these projects are far from an academic exercise. In fact, the first iGEM student project that Lynn headed, in 2011, resulted in a project called PowerCell that’s now a secondary payload on a German satellite. And as a civil servant working for NASA, a government entity, she can only serve as adjunct faculty at Stanford and Brown — teaching work for which she is not paid. And she doesn’t want to be. She just wants to use her position to “create wormholes” that connect her students to NASA and the global scientific community. “It’s the discovery,” she told me. “That’s the thing.”
Here’s the BioDrone team’s wiki.
*Which is crazy complicated, but basically what happens is that the “stop codon” in a strand of RNA (the codon responsible for stopping translation, the accretion of amino acids in a chain) gets recontextualized, so that the cells with this newly recontextualized codon won’t allow their genetic material to be expressed into any other environment. The result is something like creating a new computer operating system on a cellular level — remember how once upon a time viruses would corrupt computers running Windows, but they couldn’t get into Macs? It’s like that. I think.
**According to Lynn, the proof of concept for this functionality has been borne out. Earth organisms can theoretically grow on Mars. For instance, a bacteria called synechococcus can thrive in salt crusts. The salt crusts can attenuate UV radiation, but the bacterium would still need liquid water in order to replicate, and while there’s no liquid water on the surface of Mars, there’s still a chance of subsurface aquifers.