DNA Nanorobots Mimic Viruses to Potentially Treat Disease

DNA nanorobots sound like something out of the X-Files, but it isn't science fiction - the concept has already been proven. The Wyss Institute for Biologically Inspired Engineering at Harvard University built such a device back in 2012. Its theoretical purpose was to find specific cells, such as leukemia cells, using a logic process - and then to release an antibody to effectively destroy the cell.

So-called nanorobots incorporate DNA strands that have been programmed to fold into various 3-D configurations that form the building blocks for the nanorobots; it has been referred to as "DNA origami" for its resemblance to the Japanese paper-folding technique. The final device is intended to determine and assess its environment, decide how to respond to it, and execute the response - just as in the above example with cancerous cells.

The potential for novel treatments using this method is obvious and enormous. However, there are still many challenges to overcome, and our own bodies pose one of the more difficult challenges.

Our bodies are quite adept and efficient at fighting off foreign invaders in our systems, whether they mean harm or not. If a potentially targeted cure against a disease is attacked and destroyed by our natural defenses before it can reach the targeted area, it doesn't matter how effective of a cure it is.

The Wyss Institute research team verified this challenge, finding that when DNA nanorobots were injected into mice, they were rapidly broken down. The team solved this problem in a novel way by mimicking a material known to sometimes defeat the body's defenses - viruses. Their work was published in a recent online edition of ACS Nano.

The viral mechanism chosen for nanodevice protetction was a layered envelope approach. A solid casing of proteins surrounds the nanodevice, and two layers of an oily type of coating known as a phospholipid surround the protein casing. The coating is similar in nature to the membranes around living cells, and it allows the viruses to pass through the immune system without harm.

A DNA strand folded into an octahedral shape was the base form to be protected. Further modifications of the DNA included "handles" for attachment of the lipids. The attached lipids guided a self-assembly process to produce the two-layered surrounding membrane.

To verify the effects in the bloodstream of mice, protected nanorobots were infused with fluorescent dye and tracked through the mice's bodies. Unprotected nanorobots were used as a control.

Protected nanorobots caused the entire bodies of the mice to glow for several hours, indicating full distribution and protection throughout the body. On the other hand, only the bladder glowed in mice injected with unprotected nanorobots, indicating rapid breakdown.

It appears the research team has completed the first two elements of the drug treatment strategy - creating the devices and devising a way to protect them from being broken down in the system. Now comes the most interesting part - incorporating the mechanism of treatment for specific diseases and testing the entire process. Given the success so far, futuristic treatment methods may not be as far away as we think.