Researchers are finding that DNA’s ability to self-assemble could open up new possibilities in nanotechnology.
DNA is normally found in two biopolymer strands that coil around each other to create the famous double helix form. The strands themselves are made up of nucleotides that join together in covalent bonds – more or less the way you join Legos together. It is this ability to “self-assemble” that engenders much of the excitement about the potential of DNA as a nanoconstruction material.
At the Biodesign Institute at Arizona State University, researchers see opportunities in using DNA to assemble nanotools for medicine, space exploration, and advanced electronics.
The first “self-assembled” two-dimensional DNA nanomaterial was developed at Columbia University in 1998. This research was seen as important enough to be supported by the Office of Naval Research, the Army Research Office, the National Science Foundation, and the National Institutes of Health. Nanorobots of sizes so minute they were previously only imaginable can now be put to use in surgeries and medical exploration, to monitor the health of astronauts, and to explore extraterrestrial environments microscopically. Nanorobots and sensors can potentially provide a level of detail that will eventually provide massive amounts of information to improve our understanding of everything from the formation of the universe to quantum physics to climate science.
Some issues have plagued the technology, though, including sensitivity to temperature, and a limitation in the ability to create structures in left- and/or right-oriented versions – a critical difference in chemical structure. Another challenge was to “grow” the 2-dimensional structures into 3-dimensional structures, again expanding the potential applications of the structures. New technology from the Wyss Institute for Biologically Inspired Engineering at Harvard University has resulted in the development over a hundred 3-dimensional nanostructures using auto-assembled DNA building blocks. The process is known as “DNA origami,” but is a programmable process of “folding” DNA strands into shapes, such as tubes or spheres, that fulfill a given purpose.
Working with DNA enables innovators to assemble complex structures from building blocks smaller than a grain of dust.
Also at the Biodesign Institute at the University of Arizona, researcher John Chaput has created the first self-assembled nanostructures made up entirely of glycerol nucleic acid, which is a synthetic version of DNA. A slight change in composition enables these structures to be created in mirror-image form as well, increasing the variety of structures available to the nanoengineer. Interestingly, though GNA resembles DNA in most ways, some structural differences mean that GNA has some different properties, such as better heat and temperature resistance.
DNA is also being applied to nanocomputing, the technology involved in creating computers tiny enough to work inside cells and inside molecules. In the past, silicon has been the material of choice for superconducting, and will probably remain so for quite some time. But DNA computers are being developed that, though slower than silicon, can be made so tiny they can work on a cellular or molecular level, greatly increasing our potential to deal with illnesses at a genetic level, and engineering challenges at a molecular level. As the magazine The Economist describes, “Rather than encoding ones and zeroes into high and low voltages that switch transistors on and off, the idea is to use high and low concentrations of these molecules to propagate signals through a kind of computational soup.”
These technologies promise developments in medical science and engineering that can potentially change our world, and how we deal with diseases, exploration, and computational technology.