These results are from computer simulations but give cause for 
concern.


        http://electrons.psychogenic.com/modules/altern8news/article.php?storyid=59

New Scientist

        http://www.newscientist.com/article.ns?id=dn8439

Brightsurf

        http://www.brightsurf.com/news/headlines/view.article.php?ArticleID=22037



______________________

"The binding energy between DNA and buckyballs is quite strong," 
Cummings says. "We found that the energies were comparable to the 
binding energies of a drug to receptors in cells."

It turns out that buckyballs have a stronger affinity for DNA than 
they do for themselves. "This research shows that if buckyballs can 
get into the nucleus, they can bind to DNA," Cummings says. "If the 
DNA is damaged, it can be inhibited from self-repairing."

Computer simulations
The computer simulations showed that buckyballs make first contact 
with the DNA molecule after one to two nanoseconds. Once the C60 
molecules bind with the DNA, they remained stable for the duration of 
the simulation.

Researchers tested the most common forms of DNA, the "A" and "B" 
forms. The "B" form is the most common form. In a stronger saline 
solution, or when alcohol is added, the DNA structure can change to 
the "A" form. A third, rarer form, "Z," occurs in high concentrations 
of alcohol or salt and was not tested.

The researchers found that buckyballs docked on the minor groove of 
"A" DNA, bending the molecule and deforming the stacking angles of the 
base pairs in contact with it. The simulations also showed that 
buckyballs can penetrate the free end of "A" form DNA and permanently 
break the hydrogen bonds between the end base pair of nucleotides.

As expected, the buckyballs bound most strongly to single helix DNA, 
causing the most deformation and damage. While buckyballs did bind to 
"B" form double-strand DNA, the binding did not affect the overall 
shape of the DNA molecule. More research needed

What the researchers don't know is whether these worrisome binding 
events will take place in the body. "Earlier studies have shown both 
that buckyballs can migrate into bodily tissues and can penetrate cell 
membranes," Cummings says. "We don't know whether they can penetrate a 
cell nucleus and reach the DNA stored there. What this study shows is 
that if the buckyballs can get into the nucleus they could cause real 
problems. What are needed now are experimental and theoretical studies 
to demonstrate whether they can actually get there. Because the 
toxicity of nanomaterials like buckyballs is not well known at this 
point, they are regarded in the laboratory as potentially very 
hazardous, and treated accordingly."

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