Scientists have developed nano-robots that can deliver deadly payloads to unhealthy cells.

Researchers at Wyss Institute for Biologically Inspired Engineering at Harvard University developed these nanoscale robots that are made from DNA in the hopes that they will one day be used to fight different diseases and even cause cancer cells to self-destruct.

"People already know about using antibodies to kill cells," said Shawn Douglas, a technology fellow at the Wyss Institute. "The selective targeting and exposing the payload, that's the big novel thing."

The tiny robots were constructed using a method called "DNA Origami" in which the structure of DNA's complementary chemical base pairs is used to produce different structures. The researchers designed the DNA to operate just like a computer. The DNA was structured to form a barrel that contains the antibodies inside. When the DNA encounters a particular molecule, the barrel opens and releases the chemicals stored inside.

"We've been working on figuring out how to build different shapes using DNA over the past several years, and other researchers have used antibodies as therapeutics, in order to manipulate cell signalling, and yet others have demonstrated that aptamers can be used to target cancer cell types," Dr. Shawn Douglas, a lead author of the study told BBC News.

"The novel part is really integrating all those different pieces and putting them together in a single device that works."

In the lab the nano-robots were successful in targeting lymphoma and leukemia cells and leaving the healthy cells alone. However the team had to use 100 billion copies of the robot to treat the cells in the petri dish. For real life trials in animals the researchers will have to make trillions of nanobots. The team also has to find a way to modify the particle from being attacked by the kidneys or the liver before they can deliver their payloads.

"My dream is for one of these devices to ultimately go through clinical trials and become an actual therapeutic that would be a novel treatment for some type of cancer," Douglas said.

It might take years before nanobots can be used for human tests but it still marks a breakthrough in medicine. The DNA system makes it a safe method since it's compatible with biological systems and is naturally biodegradable. The method will also limit the toxic side effects of cancer treatments because the robots target the cancer cells and thus will require lower doses to be effective.