Lego, Eat Your Heart Out
Single-stranded DNA has already proven itself to be a useful addition to the nanotechnologist’s toolbox. Blocks of DNA have been programmed to automatically build themselves into nanoscopic structures; a very long strand can be intricately folded into complex 3D shapes through a process known, appropriately, as DNA origami. Scientists hope that eventually, the DNA programmes could be sophisticated enough to churn out miniscule therapeutic devices that could work inside the body, and even be used to do highly specific tasks, like ferrying drugs to specific sites.
Usually, the long, single-stranded DNA required comes from a virus, which raises the possibility that the body could attack the structures - but not anymore. Peng Yin and colleagues at Harvard University have designed a similar technology that relies entirely on synthetic DNA - no viruses allowed.
"Our structures could be made to be highly biocompatible," he says.
Instead of folding one long strand of viral DNA, Yin’s team designed short, synthetic DNA strands that can fold into a small tile. (And I mean seriously small - just 7 by 3 nanometres). “Each tile acts like a Lego block,” says Yin. Tiles automatically interlock with neighbouring tiles that carry a complementary DNA sequence. This means that with a bit of forward planning, the team could design a complete set of tiles that lock together to create more than 100 shapes - including any letter of the alphabet.
Scientists hope that synthetic DNA shapes could dodge the immune system, buying them more time to shuttle drugs to the right tissue. Yin believes they could be the future: The body’s own therapeutic system, designed by our cells and for our cells.
To read the original article, published in Nature, click here.
Image, top: The alphabet generated by Yin and colleagues during their experiment.
Image, bottom: Another set of images generated by Yin and colleagues, showing the infinite variety of shapes the DNA can combine into and detailing the advantages for targeted therapeutics.
Images, centre line: A computer rendering of how the DNA might fold into the tile structure.