Nano-sized “Ninjas” To Help Fight Disease (Leonardo)
WWLD: What would Leonardo do? Leonardo Da Vinci was fascinated by machines and by the human body, so if he were alive today, I think he would want to be at the cutting edge of engineering and biology. He’d be making nano-sized bio-machines.
DNA Origami• The chemistry of DNA makes it possible to to construct shapes at a very tiny scale: 1/10,000th the width of a human hair, or 100 nanometers.• We know about DNA taking a Double Helix shape, because that’s how our body’s DNA arranges itself. But DNA also arranges into more complex shapes such as the Holliday junction.
DNA Origami• We have learned how to arrange DNA into unique shapes that are only hinted at in nature.• We can make lattices of DNA that look and work like tiny boxes or baskets.
Programming the robots• These latticework DNA structures can be built into “robots” that can be programmed to follow increasingly complex instructions.• These small machines can do a lot of diﬀerent things. Some them can even “walk” using tiny legs along a programmed path.• But the most promising medical application seems to be clamshell or cylindrical containers that can enclose a beneﬁcial payload.
Nano-sized healers• The robot is shaped like a cylinder, and it has a chemical “bullet” inside, such as a drug or antibody.• When the DNA encounters a certain molecule, such as a protein found only on the surface of a cancer cell, it can be programmed to “open” and release its payload. “Aptamers” that act as clasps and sense the target cell Room for 12 molecules inside
They sense the target cell and deliver their payload
What stands in the way of this invention?• The clasps on these DNA robots are programmed to detect the surface of a target cell, but the payload often must penetrate to the interior, so we may still need to invent a can opener for these ninjas to get inside.• DNA-based robots are susceptible to being cleaned up by the liver or by enzymes in the body, so they we may still need to invent protective ninja suits for them.• Maybe they can be given a disguise based on the body’s own cells that allow them to circulate in the bloodstream for a long period of time.
For more information:• http://www.nature.com/news/dna-robot-could-kill-cancer-cells-1.10047• http://spectrum.ieee.org/robotics/medical-robots/dna-robot-could-deliver- cancer-drugs• http://www.sciencemag.org/content/335/6070/831