Researchers create DNA buckyballs for drug delivery

Scientists in the US have been using DNA buckyballs as a nanoscale building material, constructing geometric shapes and even working mechanical devices with the hope of developing this technology for drug delivery, using synthetic DNA as building blocks.

DNA buckyballs are tiny geodesic spheres that could also be used for chemical reaction containers. Under the right conditions, carbon atoms can link up into hexagons and pentagons, which in turn assemble into spherical shapes (technically truncated icosahedrons) resembling geodesic domes

Instead of carbon, the researchers from Cornell University 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.)

The aim of this research could open the door for the use of this much-researched form of carbon as a drug delivery vehicle. Buckyballs have also shown great promise in applications as diverse as pharmaceuticals, fuel cells, batteries, and coatings.

Dan Luo, Cornell assistant professor of biological and environmental engineering in whose lab the DNA structures were made, said that drugs could be encapsulated in buckyballs to be carried into cells, where natural enzymes would break down the DNA, releasing the drug.

Luo also added that DNA buckyballs may turn out to have unusual electronic, photonic and mechanical properties, and that because DNA is easily labelled and manipulated, his research group's work offers a way to study in detail the self-assembly process, a process very important to the future development of nanotechnology.

Buckyballs, whose chemical notation is C60, are hollow, soccerball-shaped molecules containing 60 carbon atoms, also known as buckminsterfullerene. Their diameter is just one nanometer, and their discovery in 1985 is regarded as an early milestone in the field of nanotechnology.

While buckyballs show great promise some scientists and activists have raised concerns about their potential toxicity to humans and animals.

Even miniscule alterations to the surface of the buckyballs can dramatically affect how toxic they are to individual cells. Toxicity is desirable for example, for particles that kill cancer cells or harmful bacteria. In other cases, like applications where particles may make their way into the environment - toxicity is undesirable.