Not all nanoparticles are created equal

By Katie Bird

- Last updated on GMT

Related tags Nanotechnology

It is clear that nanoparticles may behave differently from their macro counterparts; however, the tendency to lump them all together is misguided.

Nanoscale particles in consumer products are on the increase. But, what appears to have been forgotten in much of the ‘nanotechnology’ discourse is the diversity of materials, their properties and their respective risks and benefits that the term encompasses.

In sunscreens, nanosize particles of titanium dioxide and zinc oxide are often used as the smaller particles have better absorption characteristics. In addition, the smaller the particle the more transparent the resulting formulation will be, avoiding the unsightly white look of high SPF products.

However, critics claim that we do not know enough about how nanoparticles behave and therefore should not be using them in consumer products.

Cross barrier argument

Some argue that the smaller size may enable the particles to cross barriers in the body that their larger cousins cannot, others argue that we don’t know how these particles will behave in the environment post consumer use.

Either way, in order to make informed decisions about the safety of nanoparticles in consumer products each must be judged on its own merit.

Early in 2008 the Soil Association banned all manmade nanoparticles in its organic certified products, referencing evidence that suggests nanoparticles behave differently to macroparticles of the same material.

For the organic certification authority, research is lacking on how nanoparticles behave, so it has adopted the precautionary principle and said ‘no to nano’.

Research gives the backing

But, the industry argues that although this might be the case for nanoparticles in general, those used in cosmetics and sunscreens are backed up by significant research highlighting their safety.

The Royal Commission on Environmental Pollution also echoed the importance of not grouping all nanoparticles together when judging their potential risks.

Last year’s report from the Commission called for more testing and regulation whilst making clear that a material’s potential toxicity should be judged on its functionality and not on its size.

In other words, although the behaviour of a material in the nanoscale may well differ from the macro, this does not mean that all nanoparticles will behave in the same way.

The message is clear. Judge nanomaterials by looking at what they do and are capable of doing rather than assuming they are a single class of materials with unifying properties.

Katie Bird is a science reporter writing on industry-related issues in several Decision News Media publications. If you would like to comment on this article, please e-mail Katie.Bird 'at'

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