Testing method developed to assess safety and health risks of
nanomaterials
15 February 2006
University College Los Angeles (UCLA) has developed a new testing
strategy to help manufacturers monitor and test the safety and health risks
of engineered nanomaterials. Currently no government or industry regulations
exist for this emerging technology.
Nanotechnology involves manipulating atoms to create tiny molecules,
smaller than one one-thousandth the diameter of a human hair. ("Nano" means
"one billionth of a meter"). At such a small size, materials exhibit
unconventional physical and chemical properties that allow them to perform
amazing new feats in the areas of electronics, optics, sensoring, material
strength, catalysis, and drug delivery.
Engineered nanomaterials are already being used in sporting goods, tyres,
stain-resistant clothing, sunscreens, cosmetics, and electronics and will
also be utilized increasingly in medicine for purposes of diagnosis, imaging
and drug delivery.
The ability of nanotechnology to interact with biological materials leads
to the possibility that they may be harmful to humans and the environment.
Current understanding of the potential toxicity of nanoparticles is limited,
but research indicates that some of these products may enter the human body
and become toxic at the cellular level, in various body fluids, tissues,
and/or organs.
A review article in the Feb 3 issue of the journal Science by Dr. Andre
Nel, Professor of Medicine at the David Geffen School of Medicine at UCLA
and a member of the California NanoSystems Institute (CNSI), presents a
discussion on the potential toxic effects of nanomaterials and the urgent
need for developing safety testing.
Recognizing a need to develop a rational, science-based approach to
nanotoxicology, Nel and his UCLA team have developed a new testing method to
assess the safety and health risks of engineered nanomaterials. Nel is also
establishing NanoSafety Laboratories Inc. (NSL) in association with CNSI at
UCLA to help manufacturers assess the safety and risk profiles of engineered
nanomaterials.
The testing model developed at UCLA is based on toxicity testing for
occupational and air pollution particles, which include nanoparticles.
Nanoparticles are the most toxic ingredient in these environmental
pollutants. A mature toxicological science has emerged from the study of
these particles, providing a framework for a predictive testing strategy
applicable to engineered nanomaterials.
A predictive strategy is one in which a series of simple but high quality
tests can be employed to predict which materials could be hazardous, and
therefore speed up the process of classifying materials into those that are
safe and those that could pose toxicity problems. This type of approach is
similar to that used by the National Toxicology Program for evaluation of
chemical agents.
Nel’s model predicts toxicity according to the ability of some
nanoparticles to generate toxic oxygen radicals, which are highly reactive
forms of oxygen that can cause tissue injury, including inflammation and
other toxic effects. For air pollution particles, this injury can translate
into asthma and atherosclerotic heart disease. Using this model, Nel’s
laboratory has developed a series of tests to assess nanoparticle toxicity
in non-biological environments as well as in tissue cultures and animal
models.
“We can use the strong scientific foundation of air pollution particle
testing to help understand the health impact of engineered nanoparticles and
ensure safe manufacturing of nanoproducts,” said Nel, co-director of the
Southern California Particle Center and UCLA Asthma and Immunological
Disease Center.
The review in Science addresses questions about occupational and
inhalation exposures to nanoparticles and outlines the properties of
nanomaterials that need to be considered for toxicity testing.
The impact of nanoparticle interactions with the body are dependent on
their size, chemical composition, surface structure, solubility, shape, and
how the individual nanoparticles amass together, according to Nel.
Nanoparticles may modify the way cells behave and potential routes of
exposure, include the gastrointestinal tract, skin and lungs. The three key
elements of the toxicity screening strategy should include the physical and
chemical characterization of nanomaterials, tissue cellular assays and
animal studies.
“An understanding of nanotoxicity could also lead to the harnessing of
their properties such as using nanoparticles that initiate cell death to be
used for targeted chemotherapy approaches,” said Nel, who also leads the
Cellular Immunology Activation Laboratory in the Jonsson Cancer Center at
UCLA.
Nel is a pioneer in researching and documenting the adverse health
effects of air particles in the lung and cardiovascular system. He has
studied the ability of particles to generate reactive oxygen radicals and
oxidant injury, and the resulting effects on airway inflammation, asthma and
atherosclerosis. His laboratory has become a leader in studying the adverse
health effects of ultrafine (nano-size) particles in the body, including
methods for predictive toxicity testing.
Funding for the research on air pollution particles, that contributed to
this paper, came from the National Institute of Environmental Health
Sciences and the US Environmental Protection Agency.
Additional authors of the review article include Tian Xia and Ning Li,
Department of Medicine, David Geffen School of Medicine and Lutz Mädler,
Department of Chemical and Biomolecular Engineering, UCLA.
Further information: www.cnsi.ucla.edu
Also see article:
More resources needed to study dangers of
nanotechnology
http://www.mtbeurope.info/news/2005/512020.htm
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