Defining nano: Size does matter

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Defining nano: Size does matter
The Atlantic Ocean separates continents; it also separates schools of thought on the definition of nanotechnology. In order to educate manufacturers and consumers on nanotechnology a definition is critical.

Current understanding and acceptance has it that nanotechnology refers to particles of around 100 nanometres. But that’s vague to say the least.

The UK’s FSA says a definition for nano needs to be finalised. The USA’s FDA says a definition could be misleading. So who’s right?

Nanotechnology is an emerging area with massive potential, be it for smart packaging that lets you know when a food is really out of date, or for enhancing the delivery of nutrients in the body. As a new technology it will rightly attract interest from the public, some of whom will welcome it, perhaps warily, while others will mistrust it and will either avoid it or try to bring it down.

Stating that a regulatory body does not have an exact definition suggests that said body doesn’t really understand what it’s dealing with: How, therefore, could it possibly ensure the safety of our food supply?

Ignorance breeds fear

Does going to the nano-scale really make a difference? Well, yes. Gold is the classic example. In its bulk form gold is inert. Everyone knows this. That’s why we use it for jewellery – it won’t react with your skin.

But take gold down to the nano-scale, let’s say particles of 3-4 nanometres, and it becomes highly reactive, able to catalyse the oxidation of carbon monoxide at -20 °C, for example (which, as anyone with a basic knowledge of catalysis will tell you, is one impressive achievement).

So clearly, size does matter.

But there are worries that some in industry do not appreciate this. Toxicologist Dr George Burdock of the Burdock Group recently expressed his concerns​ about the dangers of what he sees as a lack of understanding by manufacturers, and said that this “could make nanotechnology the new asbestos”​.

While FDA may be happy to place the emphasis on manufacturers to ensure the safety of their products, if some manufacturers have no clear definition of what nanotechnology is, and its chemical implications, then where does that leave us?

So where do we stand?

The EU’s Council of Ministers recently proposed the following definition for ‘engineered nanomaterial’ as: “Any intentionally produced material that has one or more dimensions of the order of 100nm or less or is composed of discrete functional parts, either internally or at the surface, many of which have one or more dimensions of the order of 100nm or less, including structures, agglomerates or aggregates, which may have a size above the order of 100 nm but retain properties that are characteristic to the nanoscale.”

But even this does not necessarily go far enough, said the FSA, with reports stating that the agency considered this definition to lack clarity.

On the other hand, at the recent IFT Annual Meeting and Expo, Dr Annette McCarthy of the FDA said that the administration has thus far avoided being specific about what nanotechnology is.

“We do not have a definition about what nano size is. We tend to talk more in terms of impact,”​ said McCarthy.

And it would appear as if the agency has no plans to define this because putting a cut-off value, such as 100 nanometres and not 101 nanometres, could end up being misleading, she said.

I agree that putting a cut-off value on there could lead to misinterpretation: There will be occasions when 101 nanometres is just as active as 100, for example.

I also applaud FDA’s stance​ on assessing the impact that a change from the micro- to the nano-scale could produce on an ingredient, but let’s think about the consumer for a moment – they need to know that FDA has a clear grasp on what nano is.

The exact definition should be debated and decided upon by a working group of stakeholders to ensure the description is as all-encompassing as possible. And this group should be international with as many national safety assessors involved as possible to ensure a relatively uniform definition is accepted across the globe.

Nanotechnology has the potential to be a vital pillar in the future of food science. It would be a shame if that pillar is toppled by a lack of foundations.

Stephen Daniells is the science editor for FoodNavigator and NutraIngredients. He has a PhD in chemistry from Queen’s University, Belfast. His first post-doctoral research project in The Netherlands was a EU-wide project focussing on nano-scale gold particles. He has also worked in research in Netherlands and France.

If you would like to comment on this article, please email: stephen.daniells’at’

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