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In their lab, UCLA's Andre Nel and Tian Xia (left) examine a test method that could determine the health hazards of nanomaterials.
As nanotechnology gains more significance in the device industry, manufacturers may have to deal with the potential health risks of engineered nanomaterials. Now there is a method that could test their safety in the future.
The test, developed at the University of California, Los Angeles (UCLA), is based on a process designed for occupational and air pollution particles, including nanomaterials. The team at UCLA anticipates its work with these particles will provide a framework for application in engineered nanomaterials. Device manufacturers might even be able to apply the method to drug delivery, imaging, and treatments for diseases like cancer.
“Nanotechnology is also likely to evolve into further complexity where you will be able to make nanorobots that consist of many different nanomaterials,” says Andre Nel, professor of medicine at UCLA. He predicts that future nanomaterials could have more complex diagnostic and therapeutic applications that involve sensing out an area in the body that carries disease and then delivering treatment to the region. This could lead to the development of miniaturized robots that treat diseases, but “that's a long way off,” adds Nel.
There are many challenges in nano-technology, because new material properties are constantly being uncovered. According to Nel, the ultimate safety or hazard of a nanomaterial is linked to several principles. These include its properties, biological interaction with the body or the environment, and exposure. The test has chemical instruments that look at size and surface characteristics of nanoparticles, and enzymatic and flow cytometry that observe the generation of oxygen radicals. Humans inhale this form of oxygen, which when activated can interact with and cause harm to tissues, says Nel.
UCLA's test first analyzes a nanomaterial. It examines physical chemical properties, including composition, size, and surface characteristics, such as coatings. After assessing the material, a second string of tests looks at its ability to generate oxygen radicals.
“At the next level, we apply a set of principles called oxidative stress,” says Nel. “This is the group word used for all types of damage that oxygen radical damage causes in cells or tissues.” Each test reflects different levels of damage, the first being the lowest level, the second tissue inflammation, and the third causing cellular death. “Our method takes into consideration a wide web of potential cellular responses and damage, whereas the classical toxicological test often only looks at the third tier. If we find that a material shows hazards in the three steps, then we would classify the material as potentially hazardous and would test it in animal models.”
As the researchers gather information on the ability of nanomaterials to cause damage in an intact animal, they plan to assess the risk in humans. “The latter process is a science that is important for toxicology, but hasn't been developed at all for nanomaterials,” says Nel. It can take years, or even decades, to see problems in humans or the environment that result from exposure to toxins. By testing and classifying nanomaterials in a rapid method, Nel hopes to be able to predict potential hazards before they occur.
However, it's much too early to know whether this testing method could be applied to all nanomaterials. So far, Nel has examined about eight materials that appear most often in consumer products, but declines to name them. “The next step is to test a large number of materials to develop a true predictive method of classifying materials as hazardous or not,” says Nel. Setting up the capabilities to study the materials could take one to two years. In the second to fifth years of work, he foresees the introduction of many more materials into testing.
Miniaturizing the testing system and making it high-throughput will be important modifications, says Nel. “Hopefully by the end of the fifth year, we will have established a predictive high-throughput system to use for analyzing a lot of material simultaneously.”
Nel is hoping to launch a start-up company based on the research that comes from investigating the health effects of nanoparticles. He established Nanosafety Laboratories Inc. in association with UCLA's California NanoSystems Institute. Nel anticipates that the group will help manufacturers test the safety or risks of nanomaterials.
The National Institute of Environmental Health Sciences and the U.S. Environmental Protection Agency funded UCLA's research on air pollution.