( DNA isn't just for storing genetic code...)Self-assembled DNA buckyballs for drug delivery

Now Cornell University researchers have made DNA buckyballs -- tiny geodesic spheres that could be used for drug delivery and as containers for chemical reactions.

The term "buckyballs" has been used up to now for tiny spherical assemblies of carbon atoms known as Buckminsterfullerenes or just fullerenes. Under the right conditions, carbon atoms can link up into hexagons and pentagons, which in turn assemble into spherical shapes (technically truncated icosahedrons) resembling the geodesic domes designed by the architect-engineer Buckminster Fuller. Instead of carbon, the Cornell researchers are making buckyballs out of a specially prepared, branched DNA-polystyrene hybrid. The hybrid molecules spontaneously self-assemble into hollow balls about 400 nanometers (nm) in diameter. The DNA/polystyrene "rods" forming the structure are each about 15 nm long. (While still on the nanoscale, the DNA spheres are much larger than carbon buckyballs, which are typically around 7 nm in diameter.)

About 70 percent of the volume of the DNA buckyball is hollow, and the open spaces in the structure allow water to enter. Dan Luo, Cornell assistant professor of biological and environmental engineering in whose lab the DNA structures were made, suggests that drugs could be encapsulated in buckyballs to be carried into cells, where natural enzymes would break down the DNA, releasing the drug. They might also be used as cages to study chemical reactions on the nanoscale, he says.

The nanoscale, hollow buckyballs are also the first structures assembled from "dendrimerlike DNA." If three strands of artificial DNA are created such that portions of each strand are complementary to portions of ano
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Source:Cornell University News Service