Monday, December 19, 2005

"NANOTECH: Buckyballs may be hazardous to your DNA"

Nanotechnologists have performed theoretical calculations predicting that buckyballs, a common nanoparticle, could disrupt the functioning of deoxyribonucleic acid (DNA). These 60-atom hollow spheres of carbon can be functionalized for a variety of applications — from ultrasmall sensors to drug dispensers targeting particular sites inside the body. Buckyballs are developed for a wide variety of applications, including dry lubricants and semiconductors. The bad news is that computer simulations performed by Vanderbilt University and Oak Ridge National Laboratories researchers show that buckyballs have a strong affinity for animal DNA, attaching to it in a manner that prevents it from performing the reproductive actions necessary for cells to mount immune-system responses or even to repair themselves. Today, buckyballs are already treated like a hazardous material simply because their toxicity is unknown, said Cummings. So these calculations come at just the right time, he said, when researchers can study just how toxic buckyballs and other nanoparticles may or may not be — before they are mass-produced. Cummings' team found that buckyballs would shut down the human immune system and prevent cells from self-repairing. However, to penetrate to the DNA, the nanoparticles would first have to have an affinity for living tissue — which usually means they need to be organic like buckyballs, which are simply a form of carbon, a basic building block of life. The team's molecular model showed that buckyballs fit precisely into two spots on the spiraled helix of DNA molecules. Buckyballs could lodge at both the end of DNA strands or in minor grooves along the outside of the DNA. In either case, the binding will cause the DNA molecule to bend over to one side. The damage was most severe when the cell was reproducing by splitting into two separate helices, as it does when it divides or when it manufactures new proteins. The presence of buckyballs prevents both actions from happening.