Buckyballs could disrupt functioning of DNA NewScientist.com news service Kurt Kleiner   Computer simulations show that a common nanoparticle called a buckyball has the potential to damage DNA. The simulations suggest that buckyballs bind strongly to the DNA strands, distorting the molecules and interfering with functions like self-repair. Researchers caution that the simulations do not prove that buckyballs actually do any damage in the real world. But the work does raise another concern about possible dangers of nanotechnology. On Thursday, the US Environmental Protection Agency released a draft paper that called for more research into the safety of nanotechnology, saying that there are a number of unanswered questions about possible effects on health and the environment. The worry is that even familiar materials, such as carbon, might have completely different health effects at the nanoscale. One recent study, for instance, found that buckyballs accumulate in the brains of largemouth bass and cause cell damage. Drug delivery Buckyballs, or buckminsterfullerenes (C60), are hollow spheres made from 60 carbon atoms. Because of their unique physical properties they are being considered for many applications, from drug delivery to fuel cells. Researchers at Oak Ridge National Laboratory in Tennessee, and Vanderbilt University in Nashville, both in the US, decided to investigate how buckyballs would react if they came into contact with DNA. They used standard biomolecular simulation software to model two strands of DNA, with 12 base pairs each, interacting with two buckyballs over about 20 nanoseconds. They found that the buckyballs bind strongly to DNA, with about the same energy that drugs bind to receptors on the surface of cells. When the buckyballs bound, they distorted the strands of DNA. Peter Cummings, a Vanderbilt chemical engineer, says it seems likely the interaction would interfere with the DNA's function, disrupting replication and repair and increasing mutation rates. But he cautioned that it remains to be determined if buckyballs even penetrate cell membranes, and if they do, whether they would penetrate the cell nucleus, where the DNA resides. Natural bombardment Mark Wiesner, an environmental engineer at Rice University in Houston, says that it will take experiments with actual buckyballs and DNA to tell whether the simulations hold up. "Cells are bombarded with naturally occurring nano-sized particles and appear to get by just fine, so it is not at all clear whether this speculation holds any merit in the real world," he says. Cummings also notes that at present only a few grams of buckyballs are produced in the world every year, and that to err on the cautious side scientists treat them like toxic material. Journal reference: Biophysical Journal (vol 89, p 3856)

Uploaded: 12-14-05