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Regulating nanotech is challenging, says Rajender Varma, but green chemistry could help developing countries 'leapfrog' to cleaner, healthier products.

There have been major breakthroughs in nanomaterials for use in healthcare situations and some of these have already moved beyond the laboratory into the 'real world'. Now we need to pay serious attention to their potential risk to health and to the environment, both of which are still poorly understood.

Commercial nanotechnology is expected to affect almost every industrial and manufacturing sector, including medicine and drug delivery. New nano-based products are being created and introduced at an alarmingly rapid rate. One estimate says commercial nanomaterials and nano-assisted devices will be a US$1 trillion industry by 2015. Yet producing and using nanomaterials is practically unregulated, particularly in the developing world.

There is an urgent need for oversight mechanisms. The World Health Assembly (the WHO's decision-making body) identified exposure to nanomaterials as a priority for the Global Plan of Action on Workers Health (adopted in 2007). And the WHO Global Network of Collaborating Centers in Occupational Health has selected nanotechnology as one of its key focus areas.

Not just nano

Nanomaterials are being rigorously evaluated in the United States and Europe, but implementing and enforcing such regulatory standards in developing countries has been a challenging problem for all chemical-based products, not just nano products. These countries ignore the issues at their own peril.

In India, for example, there is a long list of companies, ranging across mining and chemical industries, that have failed to address the concerns of local communities and of human rights groups. From the 1984 toxic chemical disaster in Bhopal,  to a bauxite mining and aluminium refinery in the Niyamgiri Hills, Orissa, activists have been waging long-running legal battles against toxic wastes. Environmental activism has grown with environmental impact assessments being a critical component of any newer industrial activity.

However, it is not only large multinational companies that are shifting environmental burdens, with possible adverse toxic effects on humans in to the developing world but also smaller companies within developing nations.

What to test and who should pay?

So who should pay for screening, safety assessments and regulation? These are big costs that would hit developing country companies hard. Most nanotechnology innovations originate from research groups in small start-up businesses. Whether these businesses survive may depend on the burden imposed from regulatory bodies. Small companies can be severely restricted by the costs associated with increased oversight.  Yet many of companies are catering to the needs for cheaper raw materials and products outsourced by high-cost countries.

In developing countries in particular, health and safety regulations will have to carefully deliberate who should bear the cost burden of regulatory testing. It is an important task, because the regulations will in turn play a substantial role in prioritising which risks are assessed.

The regulatory burden is further compounded by an ongoing debate on the correct way to screen nanomaterials for toxicity — whether to focus mainly on effects on cells investigated in vitro, in laboratory setting, or effects on whole animals (in vivo studies), which are more challenging, and can be more expensive.

We already know that traditional toxicological assays and models can produce conflicting and often irreproducible results for nanomaterials. So there is no single accepted screening platform.

Green chemistry

Another way to circumvent some of these challenges may be to focus on the emerging area of 'green chemistry' to reduce or eliminate hazardous substances in the design, manufacture, and application of chemical products which also holds promise for reducing toxic health effects of nano-based entities. The use of eco-friendly and biodegradable materials in the production of metal nanoparticles is important for pharmaceutical and biomedical applications.

Generating nanoparticles often requires toxic and aggressive chemical reducing agents like sodium borohydride and hydrazine, a capping agent to stabilize the particles, and volatile organic solvents such as toluene or chloroform. Although these methods may successfully produce pure, well-defined metal nanoparticles, the material, environmental and health cost of production is high. We urgently need to develop more cost-effective and benign alternatives.

Leapfrogging to greener nanotech?

My own team has already developed several benign methods which use natural renewable resources such plant extracts, biodegradable polymers, polyphenols from tea sugars and even an agricultural waste such as grape pomace.

These sorts of advances could help developing nations, particularly those rich in renewable plant-derived raw materials, generate nanomaterials and nanocomposites more safely. For example, Tata Chemicals in India recently introduced a water purification technology for rural communities that uses silver nanoparticles supported on rice husk-based cellulosic material and costs only US$21 per filter. It is at an early stage of development yet is expected to be widely applied and distributed around the globe.

Such simple yet innovative strategies could allow the developing world to 'leapfrog' to greener, less-toxic nanotechnology, much as cell phones have avoided the need for enormous landline infrastructure.

Applying green chemistry principles to the development of new nanomaterials and applications is all the more significant at this early stage of nanotechnology development and could lead to new global 'design rules' for high-performance nanoscale substances that are eco-friendly and benign to human health.

Rajender Varma is a senior scientist at the Sustainable Technology Division, National Risk Management Research Laboratory, US Environmental Protection Agency in Cincinnati, Ohio, USA.

This article is part of a spotlight on Nanotechnology for health.

This article was authored by a US government employee. The views expressed in this article are those of the author and do not necessarily reflect the views and policies of the US Environmental Protection Agency. The use of trade names does not imply endorsement by the US government.

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