Green chemistry and nanotechnology

A proactive approach to nanotechnology will benefit industry, says University of Oregon chemist James Hutchison

As with other ‘next big thing’ technologies, questions have been raised about the potentially adverse health and environmental effects of nanotechnology. With this in mind, scientists and policymakers have launched a public debate on safe nanotechnology. Here we discuss the issue with James Hutchison, a professor of chemistry at the University of Oregon. Hutchison recently gave a talk on the subject of green nanotechnology to the annual meeting of the American Association for the Advancement of Science.

What is green chemistry?

“Green chemistry applies a set of principles to reduce or eliminate the use or generation of hazardous substances during the design, manufacture and use of chemicals. It is a different approach to protecting human health and the environment, because it strives to eliminate hazards associated with new products or processes, rather than manage those hazards through exposure controls. It is a voluntary, proactive approach, and one that has been shown to spur innovation while reducing hazard.”

In what way does green chemistry apply to nanoscience and technology?

“Engineered nanomaterials are new chemical species, thus the principles of green chemistry readily apply to their design, production and use. The application of green chemistry to nanomaterials involves proactive design of engineered nanomaterials, and safe, efficient production of those materials.

“Green chemistry principles help guide the design of new nanomaterials that have both optimised physical properties and reduced hazards. The principles also guide development of improved production methods that eliminate the use of toxic substances and enhance efficiency.”

How will it facilitate commercialisation of the industry?

“There are two facets to this issue. Firstly, many of the nanomaterials production methods are ‘discovery methods’ that provide access to new materials, may not scale well, utilise hazardous materials and generate large volumes of waste. To facilitate commercialisation, new production methods will be needed, and green chemistry is well-suited to address these challenges.

“The second facet involves nanomaterial safety. Green chemistry and a proactive approach to determining the structural features of nanomaterials that influence toxicity/eco-toxicity will allow the design or re-design of nanomaterials that provide high performance, but low hazard. On the other hand, an approach that relies only on risk assessment of materials that are being commercialised does not provide the necessary solutions in the event that products are found to be hazardous.

“Green nanoscience simultaneously develops alternatives that could be used as replacements for materials that are found to be hazardous. Thus, both proactive design and the development of safer, alternative materials would facilitate commercialisation.”

How would you advise regulatory authorities to deal with the challenges that nanotechnology presents?

“One of the unique challenges is the lack of tools needed to predict hazards. To address this issue, careful studies of the biological effects of well-defined series of nanomaterials are needed to build our knowledge base. This is what I referred to above as a proactive approach. Another challenge involves characterisation of the materials. It is relatively straightforward to assess size and shape, but what about surface functionality and impurity profiles? These will be key factors in nanomaterial safety. We need to develop new methods for assessing surface function and purity as well the methods for controlling them.”

Tell us about your solvent-free nanoparticle purification technique.

“We have found that nanomaterial purity has strong influence on nanoparticle reactivity, self-assembly and toxicity. Although this is not surprising, during the ‘discovery phase’ of nanoscience, little attention has been paid to the role of small molecule impurities on nanomaterial properties.

“Purification methods often consist of solvent washes to remove impurities. This approach is wasteful, and not completely effective. We developed an approach that uses nano-porous filtration membranes to rapidly separate small molecule impurities from the desired nanoparticles. In addition to being rapid and convenient, in many cases it can be accomplished without the use of organic solvents, significantly decreasing the waste generated in nanomaterial production.”

James Hutchison

James Hutchison is a professor of chemistry and Director of the Materials Science Institute at the University of Oregon. His research interests are in materials chemistry and nanoscience. Hutchison played key roles in developing the University of Oregon’s programme in green organic chemistry, and launched the university’s centre for green nanoscience. He founded, and now leads, the University of Oregon’s Safer Nanomaterials and Nanomanufacturing Initiative.

Further reading

Oregon Nanoscience and Microtechnologies Institute

Weare et al. – Improved Synthesis of Small (dCORE 1.5 nm) Phosphine-Stabilized Gold Nanoparticles, J. Am. Chem. Soc. 122, 12890 (2000) (subscription required)

Sweeney et al. – Rapid Purification and Size Separation of Gold Nanoparticles via Diafiltration, J. Am. Chem. Soc. 128, 3190 (2006)

Article first published in Nanomaterials News.