Posted: July 2, 2008

Keeping nanotechnology safe

(Nanowerk News) As with any emerging technology, nanotechnology has had its image problems. The study and use of nanoparticles, or tiny pieces of matter measuring between 1-100 nanometers, has been alternately trumpeted as the key to our future and condemned as a scourge to our health and the environment.
But amidst the enthusiasm and fear that dominated news stories in the early part of this decade, researchers in the field remained realistic in their assessments, seeing both nanotechnology's potential-to make stronger materials, diagnose and treat disease, and produce energy-and its drawbacks, which include the unknown effects of nanoparticles' interactions with living organisms.
There are signs that as nanotechnology research and development have matured, its potential applications are becoming more widely adopted by society. In fact, while it can be hard to distinguish fact from manufacturers' claims, nanomaterials may be used already in hundreds of consumer products, including sunscreens, fabrics, and computer hardware. And firms seeking to commercialize nanomaterial applications have attracted numerous investors looking to get in on the ground floor of the next big thing.
Still, there are real issues to be discussed relating to the risks and benefits of nanoparticles. By virtue of their size, shape, surface chemistry or other physicochemical characteristics, many nanoparticles exhibit properties that aren't observed in the larger, non-nanoscale form of the same material. For example, gold, a relatively inert lustrous yellow metal, can become highly reactive and appears red when suspended in a solvent on the nanoscale. Some of these properties are desirable for the intended application. Others may cause undesirable?and unanticipated?interactions with living systems or the environment.
Rice University researchers recently demonstrated that altering the surface of a cadmium selenide quantum dot, a type of luminescent nanoparticle, affects the particle's ability to penetrate a cell membrane, which in turn affects its toxicity to the cell. It is important to understand these properties and their impact on the biological world so that unwanted effects can be safely managed even as benefits are realized.
Nanotehnology Standards Needed
In order to overcome barriers to reaping the benefits of nanotechnology, industry must have standards and practices to follow for the safe development of products that incorporate nanoparticles. Standards in the areas of terminology, measurement and characterization, toxicity testing, and safe handling in occupational settings, among others, will all promote better risk management. But standards development depends on the existence of a sufficient base of information and when it comes to health and safety issues, in particular, this knowledge base is not robust enough.
A big part of the problem is that there are too many different types of nanomaterials and too many ways of purposely changing their properties to realistically test all the variants. Instead, it will be necessary to develop predictive models that relate physical and chemical properties of nanomaterials to their biological interactions. Conducting the research that would serve as a foundation for such models will take both time and money.
International Workshops
The good news is that the work to make this happen has already begun. Last year more than 70 experts from academia, industry, government organizations, and nongovernmental organizations representing the United States, Europe, and Asia participated in two workshops, one in Bethesda, MD, and another in Zurich, Switzerland, with just such predictive models in mind.
The two workshops were organized and sponsored by the International Council on Nanotechnology (ICON), a multi-stakeholder organization dedicated to the safe, responsible, and beneficial development of nanotechnology.
The first workshop, held in January 2007, focused on identifying classes of nanomaterials with common properties and potential issues in their full lifecycle assessment. Using that information, the second workshop, held six months later, focused on developing a prioritized research agenda for understanding the effects and mechanisms of nano-biological interactions.
Among the many topics covered were the potential for nanomaterials to induce oxidative stress within an organism. Which particles have this effect and which do not? Is there a correlation between the effect and a particular physical or chemical property? What might we do to a nanoparticle to control this effect to our advantage? Procedures for researching these?and many other interactions?are at the center of this work.
The objective of both workshops was to outline the research steps needed to provide predictive models within the next 10 years. Such a plan may be useful to policymakers, researchers, and technology developers who seek to direct limited resources to addressing the most pressing questions in nano safety.
The ultimate goal is to enable the design of biocompatible nanomaterials and head off any unwanted consequences of nanomaterial use.
We have gone beyond the era of wild speculation-both positive and negative-and have entered a new generation of nanotechnology research. This newest research, operating parallel to traditional research into properties, uses, and applications, seeks to make nanotechnology beneficial to humankind.
By understanding which features of nanoparticles are responsible for biological outcomes, we strive to engineer their safe use.
Source: SPIE (Kristen Kulinowski)
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