nanotehnoloogia, nanoteknologia, nanotechnologija, nanotehnologijas, nanoteknologija,
nanotechnologii, nanotecnologia, nanotehnologijo, nanoteknik
Nano Geneeskunde...Nano Medicína
Buckminsterfullerene, a form of carbon containing 60 atoms arranged like the
facets of a soccer ball and one of the first and best studied nanoscale structures,
has come under scrutiny in recent years over concerns that it may be toxic to
While media headlines have largely focused on studies
showing that C60-fullerenes, or buckyballs, are toxic
to bacterial, algae, and fish, other studies have
failed to find such toxicities. Now, a new study
from an international team of researchers suggests
that the toxic effects of these molecules may result
from the polar organic solvents used to dissolve
Reporting its work in the journal Nano Letters, a research team
headed by Fathi Moussa, Ph.D., of the University of Paris, France, studied the
toxicology of buckyballs that were modified to make them soluble in water without
the use of polar organic solvents. First, the researchers studied how “carboxylated” C60
molecules accumulated in laboratory animals
that were injected with relatively large amounts of this particular buckyball.
This experiment showed while C60 accumulated in the liver following
the largest doses, the buckyballs did not appear to trigger any apparent toxicities
as measured by the investigators.
Encouraged by these studies, the team decided to test the hypothesis that C60
can be a powerful antioxidant that
could actually protect the liver from the damage that arises from chemical exposure.
Their next experiment, then, involved first dosing rats with C60 and then administering
carbon tetrachloride, a molecule known to cause liver
damage . As the researchers expected, the animals treated with C60 did not
suffer liver damage from carbon tetrachloride, as did control animals that were
not dosed with C60 prior to receiving carbon tetrachloride.
The timing of this protection was not, however
as expected, that is, the maximum protective effect
did not occur when accumulation of C60 in the liver
was at its highest. One possible explanation for
this discrepancy, offered by the researchers, is
that the buckyballs are clumping in the liver, which
could affect their antioxidant properties.
An alternative hypothesis, suggested by researchers at the Nanotechnology Characterization
Laboratory (NCL) based on their review of the existing scientific literature,
is that buckyballs protect against carbon tetrachloride damage not because they
are antioxidants but because they kill Kupffer cells, which are believed to be
responsible for the toxicity caused by carbon tetrachloride. So despite the claims
by the investigators that this study shows conclusively that C60 is not toxic,
further work is needed to ensure that these nanoscale structures are not damaging
Kupffer cells, which play a critical role in fighting infection.
This work is detailed in a paper titled, “Fullerene is a powerful antioxidant
in vivo with no acute or subacute toxicity.” Investigators from New York University
also participated in this study. An abstract is available through PubMed. [ View
Source: National Cancer Institute