You can disguise a flash drive as pretty much anything these days: a credit card, a tube of lipstick, and even a human thumb for a literal thumb drive. But now, scientists have stored information as DNA sequences in 3D-printed versions of everyday objects, such as a bunny figurine and an inconspicuous pair of glasses.
“Let's say that someone is thinking that you're trying to take information out from a facility or from a border, and they capture you and screen all your electronic devices,” said Yaniv Erlich, the senior author of the study, which was published on Monday in the journal Nature Biotechnology. With this technology, you could conceal the information within a shirt button, he added.
All digital information boils down to a series of 1s and 0s. By creating a code that turns the four bases of DNA (A, G, C, T) into some sequence of 1s and 0s, the researchers were able to represent 3D printing instructions and a two-minute video as short DNA sequences called oligos. Next, they sandwiched the DNA inside layers of silica, forming nanometer glass beads.
From there, the beads were mixed into 3D printing material or plexiglass and made into the plastic bunny and the glasses, respectively. The plastic bunny contained the instructions needed to print a replica, and the glasses contained a video file.
To turn the DNA back into code, the researchers took a small slice of the bunny and glasses, and used a common technique to copy and read the DNA sequences contained within the objects. Even with errors caused by the underlying DNA and the reading technique, they were able to recover the information each time they tried, according to the study.
The main reason we won’t be seeing this technology in the immediate future is its cost, Erlich said. It set back the researchers $2,500 to create the artificial DNA sequences for the bunny, though the study estimates that over 10^19 “offspring” plastic bunnies could be created while retaining enough readable DNA per bunny.
“You don’t need so many bunnies in the world,” Erlich said.
Throughout the project, the researchers had to be aware of the constraints of DNA. They used plastic for the 3D printing that melted at fairly low temperatures, since DNA is degraded at high temperatures.
Still, DNA degrades slowly over time anyway, and one mistake in recovering the code from DNA to binary would make it unusable. To pre-empt this issue, the researchers designed the extraction process to be like solving a Sudoku puzzle, Erlich said. Each glass bead contained DNA with slightly different information that gave a computer clues about the hypothetical rows, columns, and diagonals of the puzzle.
“What it means is that even if you lose many of the things—namely, molecules are breaking and not making the sequences correctly—it doesn't matter because you still have enough,” Erlich said.
The plastic bunny that the researchers created is a standard 3D test model known as the “Stanford Bunny,” but the video chosen for the pair of glasses was about the Warsaw Ghetto Archives. The archives contain 25,000 pages of historical documents hidden by Jews in metal boxes and large milk cans during the Holocaust.
Beyond run-of-the-mill international espionage, Erlich said that the technology can be applied to security and medical realms, too. Cryptocurrency enthusiasts might store their Bitcoin password in the DNA beads, or doctors might record patient information in dental implants for future check-ups. The nanometer-sized beads can even be ingested and excreted, in theory providing a last-ditch option for information smugglers, Erlich said.
Still, people working for good may have reasons to use this technology, too. “Good people need to hide information," Erlich said, "so why not give them more options?”