Size Matters: New DNA Buckyball Building Blocks Could Help Deliver Drugs

Cornell University (Ithaca, NY) scientists have pioneered a method of using nano-sized, DNA building blocks to form buckyballs for drug delivery applications.

Though the notion of using buckyballs (i.e., hollow nanostructures shaped like soccer balls or geodesic domes) for drug delivery is not new, the Cornell DNA-based material is novel. While most fullerene buckyballs are constructed of carbon atoms, the Cornell scientists have made a branched DNA–polystyrene hybrid. The synthetic DNA is engineered to have no genetic function and therefore can be used as the scaffolding rods to make the buckyballs.

For reasons still being explored by the group, DNA–polystyrenes spontaneously self-assemble to make a larger hollow structure that is exactly the same shape as one buckyball. The new structure is approximately 400 nm in diameter and has 15-nm rods forming the structure. “If you calculate the volume, our buckyball is about 200 millionfold larger than the buckminsterfullerenes (i.e., carbon buckyball 60),” notes Dan Luo, head of the research group and assistant professor of biological and environmental engineering at Cornell.  “We don’t know how they form it, but we estimate in our model there are 19,000 of those building blocks that are self-aligned into one gigantic buckyball.”

This larger size may help facilitate drug delivery, according to the group, because it falls within the ideal range of cell endocytosis. “In order words, the cell can eat up the buckyball structure and the drug can get inside the cell. We think it’s biocompatible, but we’re still doing research on that,” explains Luo.

Because the structure is hollow inside and has crevices on the outside, the researchers hope the structure will be able to carry not only drug molecules, but also fluorescent trackers into the body, an application they are currently exploring. “We could use it like a barcode so that we can detect the molecule inside the cell,” says Luo. “We are trying to use our engineering techniques together so that you not only have a drug delivery vehicle, but you have a tracking vehicle.” The group also is exploring techniques to make their buckyballs easy to produce on a large scale.

–Kaylynn Chiarello