[Paleopsych] New research raises questions about buckyballs and the environment

Steve Hovland shovland at mindspring.com
Wed May 11 00:12:54 UTC 2005

In a challenge to conventional wisdom, scientists have found that 
buckyballs dissolve in water and could have a negative impact on soil 
bacteria. The findings raise new questions about how the nanoparticles 
might behave in the environment and how they should be regulated, according 
to a report scheduled to appear in the June 1 print issue of the American 
Chemical Society's peer-reviewed journal Environmental Science & 
Technology. ACS is the world's largest scientific society.
A buckyball is a soccer ball-shaped molecule made up of 60 carbon atoms. 
Also known as fullerenes, buckyballs have recently been touted for their 
potential applications in everything from drug delivery to energy 
transmission. Yet even as industrial-scale production of buckyballs 
approaches reality, little is known about how these nano-scale particles 
will impact the natural environment. Recent studies have shown that 
buckyballs in low concentrations can affect biological systems such as 
human skin cells, but the new study is among the earliest to assess how 
buckyballs might behave when they come in contact with water in nature.
Scientists have generally assumed that buckyballs will not dissolve in 
water, and therefore pose no imminent threat to most natural systems. "We 
haven't really thought of water as a vector for the movement of these types 
of materials," says Joseph Hughes, Ph.D., an environmental engineer at 
Georgia Tech and lead author of the study.
But Hughes and his collaborators at Rice University in Texas have found 
that buckyballs combine into unusual nano-sized clumps - which they refer 
to as "nano-C60" - that are about 10 orders of magnitude more soluble in 
water than the individual carbon molecules.
In this new experiment, they exposed nano-C60 to two types of common soil 
bacteria and found that the particles inhibited both the growth and 
respiration of the bacteria at very low concentrations - as little as 0.5 
parts per million. "What we have found is that these C60 aggregates are 
pretty good antibacterial materials," Hughes says. "It may be possible to 
harness that for tremendously good applications, but it could also have 
impacts on ecosystem health."
Scientists simply don't know enough to accurately predict what impact 
buckyballs will have on the environment or in living systems, which is 
exactly why research of this type needs to be done in the early stages of 
development, Hughes says.
He suggests that his findings clearly illustrate the limitations of current 
guidelines for the handling and disposal of buckyballs, which are still 
based on the properties of bulk carbon black. "No one thinks that graphite 
and diamond are the same thing," Hughes says. They're both bulk carbon, but 
they are handled in completely different ways. The same should be true for 
buckyballs, according to Hughes.
These particles are designed to have unique surface chemistries, and they 
exhibit unusual properties because they are at the nanometer scale - one  
 billionth of a meter, the range where molecular interactions and quantum 
effects take place. It is precisely these characteristics that make them 
both so potentially useful and hazardous to biological systems. "I think we 
should expect them to behave differently than our current materials, which 
have been studied based on natural bulk forms," Hughes says. "Learning that 
C60 behaves differently than graphite should be no surprise."
Overall, the toxicological studies that have been reported in recent years 
are a signal that the biological response to these materials needs to be 
considered. "That doesn't mean that we put a halt on nanotechnology," 
Hughes says. "Quite the opposite."
"As information becomes available, we have to be ready to modify these 
regulations and best practices for safety," he continues. "If we're doing 
complementary studies that help to support this line of new materials and 
integrate those into human safety regulations, then the industry is going 
to be better off and the environment is going to be better off."
The American Chemical Society is a nonprofit organization, chartered by the 
U.S. Congress, with an interdisciplinary membership of more than 158,000 
chemists and chemical engineers. It publishes numerous scientific journals 
and databases, convenes major research conferences and provides 
educational, science policy and career programs in chemistry. Its main 
offices are in Washington, D.C., and Columbus, Ohio.

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