Nanotechnology

Nanotechnology involves the creation and/or manipulation of materials at the nanometre (nm) scale either by scaling up from single groups of atoms or by refining or reducing bulk materials. A nanometre is 1 x 10-9 m or one millionth of a millimetre. To give a sense of this scale, a human hair is of the order of 10,000 to 50,000 nm, a single red blood cell has a diameter of around 5000 nm, viruses typically have a maximum dimension of 10 to 100 nm and a DNA molecule has a diameter of 2 - 12 nm (www.nano.gov). The use of the term 'nanotechnology' can be misleading since it is not a single technology or scientific discipline. Rather it is a multidisciplinary grouping of physical, chemical, biological, engineering, and electronic, processes, materials, applications and concepts in which the defining characteristic is one of size.
 

Why is nanotechnology attracting so much attention?

 

A major reason is that ordinary materials such as carbon or silicon, when reduced to the nanoscale, often exhibit novel and unpredictable characteristics such as extraordinary strength, chemical reactivity, electrical conductivity, or other characteristics that the same material does not possess at the micro or macro-scale. This opens up a virtually infinite number of possible new applications for existing materials. To date, a huge range of materials have already been produced including nanotubes, nanowires, fullerene derivatives (bucky balls), and other nanoscale materials, and while production of many of these new, 'engineered' nanoparticles (NP) is mainly small scale in laboratory based environments, a substantial effort is currently focussed on scaling up production to an industrial scale.

The rapidly increasing activity in the areas of nanoscience and nanotechnology over the last few years has led to the foundation of large programs in the UK, Europe and the US to facilitate the development of these technologies. As a result, nanotechnologies are gaining in commercial application. To date there are over 200 nanotechnology based products available commercially on the global market. Nanoscale materials are currently being used in electronic, magnetic and optoelectronic, biomedical, pharmaceutical, cosmetic, energy, catalytic and materials applications. Areas producing the greatest revenue for nanoparticles are reportedly chemical-mechanical polishing, magnetic recording tapes, sunscreens, automotive catalyst supports, bio-labelling, electro-conductive coatings and optical fibres. Further example applications may be found on the National Nanotechnology website or through the Project on Emerging Nanotechnologies Inventory of Consumer products.

 

What's the problem then? 
 
In parallel to the massive up scaling of nanotechnologies, concerns have been growing about the potential risks to health and to the environment that could potentially result from exposure to nanoparticles. These concerns have been largely driven by earlier studies which have demonstrated that the potential toxicity of some particles increases on a mass for mass basis, as particle size decreases. Over the last three years there have been a great many (more than 30) international reviews which have considered these risks.  The consensus view emerging from these reviews is that there are potential issues of concern and that there are major uncertainties in what is known about risks to the health, in particular of workers but also of consumers, the general public and to the environment.

Assessment (and ultimately management) of risk is complex since risk is a product of both the toxicity (hazard) of a material and the levels to which people, or the environment, are exposed. So while hazard is intrinsic to a material, exposure depends on the scenario of manufacture or use. The result is a large number of interdependencies associated with the risk assessment paradigm. In practice it is seldom that all of these interrelationships can be evaluated. However to be effective, risk management needs to take account of both hazard and exposure.

Responsible development of any new materials requires that risks to health and the general environment associated with the development, production, use and disposal of these materials are addressed. This assessment of possible risks posed to public health from novel materials, requires understanding of the intrinsic toxicity of the material, the levels of exposure that may occur (by inhalation, by ingestion or through the skin), and any relationship between exposure and health effects. This is necessary to protect workers involved in production and use of these materials, the public and the ecosystem; and to help inform the public debate about the development of new, potentially beneficial, materials. However, due to the diverse nature of new nanomaterials and their radically different properties, general solutions for assessing hazard, exposure and risk have not yet been found. As a result regulation in the UK and elsewhere, does not yet reflect the potential differences between these materials in their nano and macro forms.  The problem for those involved in the development and manufacture of these materials, is that this gap in knowledge presents a barrier to evaluating and managing these risks appropriately.  To effectively bridge this gap expert input into the process is required.

 

 

What is being done?

Concerns about the lack of knowledge and possible risks arising from exposure to nanoparticles led the UK Government to request advice from the Royal Society and Royal Academy of Engineering and to the formation of their Nanoscience and Nanotechnology Working Group. Their report, published in July 2004 ( http://www.nanotec.org.uk ), makes wide ranging recommendations about the need for more and better information and for a coherent approach to these concerns.

In this report, particular emphasis was placed on the need to further understanding of the human health and environmental effects posed by nanoparticles and Nanotubes, with a view to design and implementation of appropriate regulations. In the UK and elsewhere, momentum has been gathering and a number of major international initiatives have developed to try and resolve these issues.