By bombarding insects with electrons, Japanese researchers formed a microscopically thin layer that protected them from the ravages of a vacuum. The discovery suggests a way that microbes might survive the harsh conditions of outer space — and perhaps humans as well.
Insects don’t fare well in a vacuum. When exposed to severely reduced pressure, they shrivel-up and die within minutes. But as Takahiko Hariyama and colleagues recently discovered, if the bugs are bathed in a beam of electrons, they become surprisingly tolerant to a high vacuum.
They came to this realization after placing a live fruit fly larva under an electron microscope — microscopes that only work on objects placed within a vacuum, otherwise air molecules absorb the electrons required to take the image. But after expecting the larva to quickly dehydrate, it continued to survive and thrive. And in fact, it eventually grew into a healthy fruit fly.
Writing in ScienceNOW, Sean Treacy explains what happened:
The scientists then used the microscope to peer closely at the edge of the insects' skin. They found that the energy from the electrons changed the thin film on the larvae's skin, causing its molecules to link together—a process called polymerization. The result was a layer—only 50- to 100-billionths of a meter thick—that was flexible enough to allow the larva to move, but solid enough to keep its gasses and liquids from escaping. "Even if we touched the surface [of the layer]," Hariyama says, "the surface did not break by our mechanical touch." It was almost like a miniature spacesuit.
The team dubbed the layers "nano-suits." Most insects do not have natural layers on their surfaces that become nano-suits when exposed to an electron stream, however. So Hariyama and colleagues decided to create artificial nano-suits. They dunked mosquito larvae in a pool of water mixed with a chemical called Tween 20, which is useful because it's not toxic and is commonly found in detergents, cosmetics, and hard candy. The researchers then showered each larva in plasma, so that the Tween 20 would polymerize and become a nano-suit, and moved the nano-suited larvae to the microscope's vacuum to watch what happened.
Treacy also spoke to an astrobiologist about the discovery:
The finding is "exciting," says astrobiologist Lynn Rothschild of NASA's Ames Research Center in Moffett Field, California, who was not involved in the work, because it indicates that nano-suited creatures might survive travel by a meteorite or comet through the extreme environments of space. She notes that it could also have applications for space travel. "Imagine a flexible space shield, roughly the diameter of a human hair that could protect against dehydration and radiation."
Read the entire article at ScienceNOW; and check out the study at PNAS: “A thin polymer membrane, nano-suit, enhancing survival across the continuum between air and high vacuum.”
Image: Yasuharu Takaku et al./PNAS