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Researchers have developed a way to print DNA. As this ScienCentral News video explains, that might one day make genetic testing as cheap and as accessible as a blood test.
Cheap DNA Tests
Handy genetic tools, called microarrays, have allowed scientists to delve into the genetic material that makes each of us who we are.
With the ability to run tens of thousands of genetic experiments in parallel on a small glass slide, DNA microarrays have offered better understanding of genetically-based illnesses, like Huntington's and cancer, identifying red flags for those diseases in our DNA, and finding clues to help fight them, including targets for new drugs.
Despite their great potential, microarrays, which look more like 1970's pop art than a tool of science, are not generally used in medical diagnostics. Although advances in technologies have sped up production and brought costs down in recent years, this powerful genetic tool is still too costly and complicated to make its way into the average doctor's office.
"They are supposed to be the future of diagnostics, whereby you use these to analyze all of your… genetic information, that allows you to be able to tell which are your genetic diseases or to diagnose cancer very early on," says Massachusetts Institute of Technology (MIT) materials scientist Francesco Stellacci.
So Stellacci and his colleagues have developed a nano-scale printing technique they hope might make DNA analysis an everyday thing, available to all of us. "Our dream, our long term goal, would be to bring them to a cost of… say $50 a piece… so that this analysis of DNA becomes as common as a blood test," he explains.
Drawing blood for testing image: National Cancer Institute
In the same way that the printing press revolutionized the world of publishing, the research team believes their technique could be automated to allow the cheap mass-production of a whole variety of nano-devices that are currently built one at a time. DNA microarrays take several hundred complex steps to produce.
Taking his inspiration from nature, Stellacci developed a technique that prints DNA from one substrate (surface) — for example glass, gold or silicon — onto another. Using a print template they can produce mirror-image copies in just few a simple steps — offering the rapid transfer of a large amount of information.
"I wanted to do a technique that was meant to produce stuff very quickly, but keeping their complexity. So I started thinking about the ways nature reproduces information in our body," Stellacci explains. "The beauty of this mechanism is that it's really information-rich… it's very efficient, and it happens over and over in our body. And so what I wanted to do was to emulate this in a much simpler way, not trying to do anything this ambitious, but to generate a nanotechology method of printing that would keep complexity from a substrate to another, and be able to transfer organic and biological information."
Results of DNA testing
With the new technique, called "supramolecular nano-stamping" (SuNS), the template — a surface dotted with single strands of DNA of known sequences, attached via specially engineered "sticky ends" — is placed in a solution filled with other pieces of DNA. Through molecular recognition, the complementary DNA strands each match up with the template strands and hybridize — spontaneously assemble into the well-known double helix form due to sequence-specific interactions. "The complementary sequence will end up in that spot by molecular recognition without us doing anything; we just have to wait," Stellacci explains.
After the pairing up of the DNA strands, another substrate is attached to the free sticky ends of the complementary strands, making a kind of DNA sandwich. "If we heat up at… 105 [degrees], the two DNA naturally separate without breaking anything or suffering any damage," he says, leaving the original master and a mirror image copy. The printed copies are identical to the template and can therefore be used as masters themselves to print more. "So you have almost an exponential growth of masters," Stellacci says.
The next step is to build up the number of strands of DNA on the template with the hope of one day producing a DNA microarray using this technique, printed with as many as 500,000 DNA strands of known sequence.
Beyond DNA, Stellacci's technique could be used to produce many other kinds of nano-devices: materials, both organic and inorganic (metal nanoparticles for example), can be made to assemble along a pattern composed of DNA strands. Stellacci says: "In the future one could envision using DNA just as a starting material to produce a transistor, because there are published ways where you can transform DNA into a metal, or… turning DNA into semiconductors."
He also plans to try printing with other things like proteins, antibodies and viruses.
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