of science fiction surround the potential of the
booming nanotechnology industry - like Michael Crichton's
novel "Prey", which features tiny nano-robots threatening
to take over the world. Fiction of course, but nanotechnology
is rapidly expanding and promises to exceed the impact
of the Industrial Revolution, projecting to become
a $1 trillion market by 2015.
UCLA has developed a new testing method that would
help manufacturers monitor and test the safety and
health risks of engineered nanomaterials. Currently,
no government or industry regulations exist for this
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 compelling discussion on the potential
toxic effects of nanomaterials and the urgent need
for developing safety testing.
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, tires, 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,
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
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
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
As nanomaterials are increasingly being used for
commercial purposes the NanoSafety Lab's goal is
to help corporations deal with the safety and regulatory
issues relating to the use of nanomaterials in their
products. The testing approach is based on existing
regimens and protocols in Nel's laboratory as well
as new techniques being developed by research at
CNSI, including collaboration with leading scientists
around the country.
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.