Nanoparticle safety raises questions

U.S. initiative focuses on health as well as economic impacts of nanotechnology.

By Seán Ottewell, editor at large

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“There is an urgency to nano-EHS research that affects the entire NNI investment,” stressed Vicki Colvin, director of the Center for Biological and Environmental Nanotechnology at Rice University, Houston, and executive director of the International Council on Nanotechnology, at a hearing of the House Committee on Science and Technology in late October. “Innovation in nanotechnology is being threatened by the uncertainty about its risks. We need this innovation more than ever right now.” Interestingly, she called for a detailed strategy for nano-EHS research no later than fall 2008.

Such concerns extend well beyond the U.S. For instance, a 2007 report from the Science and Research Policy Section of the European Union’s Community Research and Development Information Service, Brussels, Begium, warned that lack of toxicity data on nanomaterials is a challenge to the safe commercialization of nanotech products.

“The lack of toxicity data specific to nano-materials is a repeating theme in this and in other studies related to nanotech EHS concerns,” said Andrew Maynard, chief scientist for the project.

Meanwhile, a 32-page report released in December by insurance market Lloyd’s of London, London, U.K., cautioned that the assessment of whether or not nanoparticles harm people has barely begun. “Currently almost all regulation of nanotechnology is done using existing mechanisms,” it said. “Stakeholders in nanotechnology are divided on whether specific regulation is required. However, the ‘wait and see’ approach is increasingly becoming a dangerous way to determine the risks.”

The report speculated about a whole range of large-scale disasters that nanotechnology might prompt — for example, workers involved in nanoparticle manufacture developing chronic illnesses. Lloyd’s noted that, although the real risk of chronic health effects remains unclear, nanoparticles can enter the body and so insurers “would be prudent to consider adverse scenarios.”

The report pointed out the positive role the new materials could have on safety, such as the creation of cars that could better absorb the impact of a crash, but also warned that while nanoparticles are relatively cheap, can be manufactured in large quantities and are already used in consumer products, they can be highly reactive.

Food for thought

Human consumption of materials containing nanoparticles already is a particular area of concern.

One major driver was the announcement in March 2007 by researchers at University of California, San Diego (UCSD), San Diego, Calif., that iron-containing nanoparticles being tested for use in several biomedical applications can be toxic to nerve cells and interfere with the formation of their signal-transmitting extensions (Figure 3).

Figure 3. Cells exposed to no (left), low (center) or high (right) concentrations of iron oxide nanoparticles differed in formation of thread-like extensions called neurites. Source: UCSD.

Figure 3. Cells exposed to no (left), low (center) or high (right) concentrations of iron oxide nanoparticles differed in formation of thread-like extensions called neurites. Source: UCSD.

“Iron is an essential nutrient for mammals and most life forms and iron oxide nanoparticles were generally assumed to be safe,” said Sungho Jin, a professor of materials science at UCSD. “However, there are recent reports that this type of nanoparticle can be toxic in some cell types, and our discovery of their nanotoxicity in yet another type of cell suggests that these particles may not be as safe as we had once thought.”

A similar warning comes from Germany’s Federal Institute for Risk Assessment (BfR), Berlin, Germany, following an extensive consumer survey it completed. This found that consumers were especially critical of the use of nanomaterials in foods, with particular fears expressed about the unknown consequences of digesting nanoscale particles that are designed to behave in a specific way in the body.

Overall, clearer definitions, terms and standards — along with extensive research into its potential problems — are needed before nanotechnology finds greater use in food products, the BfR survey concluded.

Similar warnings also have been issued by the newly-merged Danish National Food Institute (NFI) and the Technical University of Denmark, both in Lyngby, Denmark. NFI is undertaking a specific project that starts with the hypothesis that the mere nanometer size of matter and its associated large surface area may lead to adverse effects in living organisms including human beings.

Clearly, EHS issues loom large in nanotechnology and the NNI plan and other efforts are essential for helping to ensure responsible development.

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