By Elizabeth Lopatto - Thu Feb 16 19:00:00 GMT 2012

Enlarge image Robot Made from DNA May Help Deliver Drugs

Campbell Strong, Shawn Douglas & Gael McGill using Molecular Maya & cadnano via Bloomberg

Cell-targeting DNA nano-robots bearing antibody fragment payloads.

Cell-targeting DNA nano-robots bearing antibody fragment payloads. Source: Campbell Strong, Shawn Douglas & Gael McGill using Molecular Maya & cadnano via Bloomberg

Scientists have created a robot made entirely from DNA that can be instructed to find diseased cells in the body and deliver a payload to kill or reprogram them, according to a study from Harvard University.

The robot was constructed by folding DNA strands into a shape that looks roughly like a clamshell. The researchers programmed the nano-sized device to open in the presence of leukemia and lymphoma cells in a laboratory dish, where they delivered immune system antibodies that caused the cells to self-destruct, according to a report in the journal Science.

The next step will be to test the system in animals, tweaking the robot so that it can circulate longer in the blood to locate all cancer cells. The technology isn’t yet ready for commercial use, said Shawn Douglas, an author of the study.

“In diseases such as cancer we know if we can find every single last cell and kill or reprogram it, we can cure that disease,” said Douglas, a researcher at the Wyss Institute for Biologically Inspired Engineering at Harvard, in Boston. “A lot of our current therapies fall short.”

The idea is based on the behavior of the body’s immune cells, which recognize viruses or other invaders and attack them, Douglas said. The DNA nano-robots, with similar capabilities, may potentially lead to the development of new types of targeted cancer treatments that kill only abnormal cells, he said.

The robots don’t reproduce. They have to be constructed in a process that has gained traction since the idea of DNA nanotechnology was first suggested in 1982.

DNA is a material, shaped in the form of a revolving ladder, which carries the genetic information in our cells.

The double-sided strands have so-called sticky ends that allow them to be joined together with other DNA. Scientists, led by Nadrian Seeman, now head of the Department of Chemistry at New York University, have used those sticky ends to form DNA into lattices that can be shaped in various ways.

The latest research created a robot in a clamshell shape that’s held together with a “zipper” constructed of a special sequence of DNA, the report said. The zipper was programmed to release its grip when it recognized specific targets on a cell, allowing the robot to release its payload.

In the experiment, Douglas and his fellow scientists used the robot they constructed to deliver instructions encoded in antibodies to the cancer cells.

“It’s an important step forward in specific targeting,” said Milan Stojanovic, an assistant professor of experimental therapeutics at Columbia University in New York who wasn’t involved in the research, in an e-mail. “It looks very exciting.”

Besides cancer, the robots may also benefit people with autoimmune disease, Douglas said. One day, the robots might be used to find immune cells wrongly attacking the body and reprogram them, he said.

To contact the reporter on this story: Elizabeth Lopatto in New York at elopatto@bloomberg.net.

To contact the editor responsible for this story: Reg Gale at rgale5@bloomberg.net.

See original here:
DNA Robots Programmed to Kill Cancer Cells, Harvard Study Shows