The Bunny Identity
3D model printed using data stored inside itself.
By Paul Biegler
Scientists may just have come up with a plot device for the next instalment of the Bourne movie franchise, in the form of a plastic bunny and a rather innocuous-looking pair of spectacles.
The story, which is published in Nature Biotechnology, begins with the rabbit.
Yaniv Erlich, a computational biologist working from the Erlich Lab LLC in Raanana, Israel, led a team that 3D printed a version of the Stanford Bunny. That’s a stock standard crouching rabbit used as a benchmark shape for testing computer graphics.
So far so unremarkable.
But they printed it using data stored on DNA inside the bunny itself. And that, to avoid a nasty case of brain fade, requires a bit of unravelling.
DNA has been touted as the solution to the world’s imminent data storage woes: the voracious appetite of the Information Age will soon gobble up the storage potential of hard drives and magnetic tape, which can only be miniaturised so far.
DNA holds the blueprint for life itself, so the idea is to repurpose that mega storage capacity for more mundane stuff like videos, books and the like.
To see how that might be done, you need to know that bits of data, in the form of 1’s and 0’s, can be neatly represented by the four DNA bases Adenine (A), Cytosine (C), Guanine (G), and Thymine (T) as 00, 01, 10 and 11.
The sequence 011100 would, for example, make the short DNA sequence CTA.
Getting your head around that makes it possible to see the myriad combinations of A, C, T and G in a strand of DNA could store quite a lot of data.
Putting an exact number on it, 215 Petabytes of data can fit in a gram of DNA. On one estimate, that’s enough to store all the music made in the last 2000 years.
Erlich’s team set out to get proof of concept for that theory, and more.
First, they compressed the data needed to 3D print the Stanford bunny down to 45 kilobytes. They then encoded that data in 12,000 strands of DNA, each 145 bases long.
To keep the DNA nice, they put it in a tiny silica bead, which was then further encased in 3D-printable thermoplastic. The initial digital file was then used to 3D print the bunny, fabricating it with those silica-plastic beads containing the DNA master plan.
The next part of the experiment is the mental equivalent of looking at yourself in a hall of mirrors and wondering if your reflection ever stops.
Clipping 10 milligrams – the weight of three grains of rice – from the newly printed bunny’s ear, they decoded the DNA concealed within and printed another bunny. Then another. And another. Five in total.
“Just like real rabbits, our rabbit also carries its own blueprint,” says co-lead researcher Robert Grass from ETH Zurich in Switzerland.
At this point, even if your mind is doing somersaults, the result may still seem like a party trick. But there is a sombre side to it all.
The whole project is an example of steganography which, from the Greek, means “concealed writing”. And one of the archetypal and most chilling feats of steganography is the story of Oneg Shabbat, which is Hebrew for “Joy of Sabbath”.
A group of Jews imprisoned in the Warsaw Ghetto in 1940, most of whom were later murdered in the Treblinka extermination camp, gathered secretly on Fridays to celebrate the Sabbath.
Unbeknownst to their captors they also collected written testimonials, drawings and photographs to document the horrors of their internment, which they buried in milk cans. The truth outlived them – the archive was recovered in the rusting cans after the war.
Erlich and colleagues pay tribute to that courageous act, using their storage technique to manufacture a pair of plexiglass spectacles with a two-minute, 1.4-megabyte video about Oneg Shabbat encoded on DNA within.
“The end result was a pair of ordinary-looking glasses with ordinary-transmittance lenses that secretly stored a video message,” they write.
Snipping off a tiny portion of the specs they retrieved and decoded the video, then played it back using Quick Time on a Mac laptop.
Some history must never be forgotten and DNA, which has been retrieved from 430,000-year-old Neanderthal bones, is a storage medium that could well be fit for that purpose.
But the authors describe still more possibilities for their tech.
3D medical implants – think personalised hip replacements – could be made with the information for their own replication implanted within, should a re-do be needed later.
And, of course, there are the Bourne applications. In a world where sensitive data seems to be getting nabbed with alarming regularity, keeping it secret is no small matter.
The authors say their technology, which they call the “DNA of Things” (DoT), could help.
“The DoT architecture... enables a wide range of everyday objects, from a keychain to a bottle lid, to be turned into concealed storage devices that can secretly carry data,” they write.
There is one final application, however, that could make a very good Bourne movie, or a rather sad plight for humans.
The team estimated there was enough DNA in the Stanford Bunny to make around 10 trillion trillion more – which raises the prickly issue of self-replicating machines.
“Our results suggest that one DoT library has sufficient replicating capacity to produce storage material for a virtually unlimited supply of objects. This can simplify blueprint transmission in self-replicating devices,” they write.
Could that lead to a world where computers breed like rabbits?
If yes, it might be time to hop it.