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The term “robot” also applies to microscopic creatures that are not made of metal and electrical wires, but of organic matter—the DNA robot. The idea dates back to the 1980s with the biochemist Nadrian Seeman’s work on DNA nanotechnology, introducing the concept of DNA origami and the construction of life at this scale. Today, medicine wants to use these robots to fight incurable diseases. This article presents the DNA robots that will be used to eradicate cancer cells.
The work of Nadrian Seeman
Nanomedicine has several challenges to overcome in order to properly use DNA robots. To treat cancer with this new generation of drugs, we must make sure that robots do not harm healthy cells.
Researchers at Arizona State University and the National Center for Nanoscience and Technology of China (NCNST) have created nanobots that can reduce tumours by cutting off their blood supply. This therapy can be used in the treatment of several types of cancer because while these cancers develop they form blood vessels that feed their growth. The research spanned five years and has at this stage resulted in conclusive results, presented in the study entitled “A DNA nanorobot functions as a cancer therapeutic in response to a molecular trigger in vivo,” published in Nature Biotechnology on February 12, 2018.
The DNA robots created by the team self-assemble from DNA strands. The construction takes place on a scale that is a thousand times smaller than the diameter of a human hair. Their structure in the form of DNA origami allows them to move and bring the drug molecules to the target, the cancer cells.
This video presents DNA origami robots:
DNA Origami, the Future of Nanomedicine and Synthetic Biology
Each robot is made from a flat rectangular origami sheet measuring 90 nm by 60 nm. The robot chain is composed of an aptamer and thrombin. The aptamer is a synthetic oligonucleotide that can bind to the nucleolin. The nucleolin is a protein found on the surface of endothelial cells involved in the formation of the blood vessels that nourish tumours. Thrombin, attached to the surface of the robot, is responsible for neutralizing the tumours. When self-assembling into a robot, the sheet folds into a tube form.
The Nanobot Carries a Double Agent
Intravenously injected DNA nanobots release thrombin into the tumor-associated blood vessels. Thrombin is an enzyme involved in blood clotting. By penetrating the blood vessels, thrombin causes intravascular coagulation leading to growth inhibition and tumor necrosis. Since nucleolin is only found on affected cells, the nanobots do not attack healthy cells.
The study also found that the nanobots present no danger to the body and are immunologically inert. A few hours after the injection, the nanobots surrounded the tumours. The experiments were conducted on Bama mice and miniature pigs. The guinea pigs had breast, ovarian and lung cancer, as well as melanoma. The study also showed that nanobots did not reach the brain where they could have caused a stroke.
This means making suitable DNA origamis, targets and specific medicinal payloads.