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.
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.
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-C 60 " — that are about 10 orders of magnitude
more soluble in water than the individual carbon
this new experiment, they exposed nano-C 60 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 C 60 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.
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.
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."
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
"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.
The cover story of the May 2 issue of Chemical & Engineering News , the ACS weekly
newsmagazine, is entitled "Nanotechnology: Ready
for Wall Street?" The article describes investment
and industry activities related to nanotechnology.
To view the article, visit http://pubs.acs.org/cen/coverstory/83/8318nanotech.html .
The online version of the research paper cited
above was initially published April 28, 2005 on
the journal's Web site. Journalists can arrange
access to this site by sending an e-mail to email@example.com or
calling the contact person for this release.