DNA Nanobots Could Deliver the Future of Medicine

What's This?

By Lance Ulanoff2013-12-05 01:30:43 UTC

Someday you will take a pill that will fix your body. Sounds like science fiction and, though not yet science fact, it is a tantalizing potential presented by a breakthrough in nano technology and biomedicine from researchers in the U.S., Denmark and Rome. Nanorobots that can deliver and release biomolecules based on temperature.

Built from molecules, this “DNA Nanocage” (sounds cool because it is) was designed by researchers, but self-assembled from the human “body’s own molecules.” The hope, while far off, is that the Nanocages could be ingestible in pill form, containing medicine to effectively trap diseases or cancers at the molecular level.

See also: FDA Puts Kibosh on Google-Backed DNA Test Service 23andMe

The tiny cage responds to surrounding temperatures to open and close its lattice. Researchers from Aarhus University in Denmark, working with teams at Duke University in North Carolina and the University of Rome in Italy, used it to hold an active enzyme called horseradish peroxidase (HRP). According to researchers, the cage’s central cavity is large enough for the enzyme, while the lattice-work holes are too small for it to escape. It releases the HRP only when the right temperature conditions exists, at which point the lattice opens wide enough to let the enzyme pass through. Awaiting cells can then consume it.

Nano Magic

Mashable spoke to Biomedical Engineering Post Doctoral Associate Sissel Juul, Ph.D., about how the DNA Nanocage works and why it matters. He has been working on this project at Duke University since 2008.

Juul told us that DNA structures are not new and are based on the core principles of DNA binding. DNA has four bases: adenine (A), cytosine (C), guanine (g) and thymine (T). Each base naturally pairs with a certain other base (always in pairs; A with T and C with G). “So the sequence of the DNA, which molecule comes after which molecule, will tell us how it will assemble,” said Juul.

The researchers then added an enzyme that links all the single strands together, leaving no open ends. Juul explained that the human body naturally degrades free DNA strands, which would effectively make the DNA Nanocage useless.

The big innovation here, however, is the DNA cage’s functional element: the ability to open and close based on temperature. Some previous DNA structures have included a molecular lock that can only be opened with an external key.

With her DNA cage “you don’t have to add anything. [You] don’t have to ruin the cage,” said Juul.

Concept and Next Steps

Don’t start lining up for your first Nanobot injection just yet. Juul cautioned that these experiments are still just a proof of concept. Even the images of the DNA Nanocages in action included here are simply computer animations produced at the University of Rome. “It’s too small to take pictures of, so it’s a simulation."

The researchers did find other physical ways of proving their work. They put the molecules on X-ray film and, because the HRP substrate emits light, it made a spot on the film and they were able to track the enzyme. They also useda Time of Flight Mass Spectrometer (TOF MS) to measure the contents of the molecules based on how long it took them to travel along the instrument’s “flight tube.”

As for what’s next, Juul doesn’t think the idea of a pill full of these things to deliver targeted medicine is all that far-fetched. “There are a lot of drug delivery mechanisms, [but] making a pill is most desirable. You don't have to open anything except your mouth."

Near-term, however, they’re working on attaching something else to the DNA cage. “Some cancer cells have specific receptors that recognize a specific molecule. So if you can add that to the cage, only the cancer cell would take it up.”

In essence, it’s the nano-sized version of the Trojan horse. The cancer cell sees an attractive molecule riding on friendly human DNA, having no idea that inside that DNA latticework is a drug that can wipe it out.

Juul believes “we will see commercial targeted non-viral drug delivery soon.” And when is that? “The question is whether a DNA based vehicle will win the ‘race’ over other nanorobots,” wrote Juul in an email. “I can't really give you a specific timeframe —sorry. It is also a matter of clinical trials and FDA approvals, which tend to take a really long time. So even if the technology is there, it might take a while.”

The waiting will be hard, but when pill-ready DNA nanocages do arrive, those cancer cells may never know what hit them.

More details on the study can be found here.

Have something to add to this story? Share it in the comments.

Image: University of Rome, Italy

Topics: biomedicine, Health & Fitness, nanotechnology, US & World, World