Nanomaterials and nanotechnology
Nanotechnology is an exciting and dynamic area of science that offers potential benefits for the future in many revolutionary ways. Nanotechnology has already been used to produce novel materials such as flame resistant plastics and textiles and it is used to make intelligent packaging that can keep food fresh and safe for longer. The communication, technology, leisure, medicine and personal care industries all use nanotechnology and nanomaterials to produce products, materials and treatments that benefit us all.
This page provides answers to the following questions:
1. What does "nano" mean?
2. What is a nanomaterial?
3. Which nanomaterials are used in cosmetics?
4. Are nanomaterials safe?
5. Can nanoparticles penetrate through the skin?
6. How will I know if a cosmetic product contains a nanomaterial ingredient?
The word "nano" derives from the Greek word "nanos", which means dwarf or extremely small. Today, in science, the term "nano" is used to indicate an extremely small scale of measurement, the nano-scale, which is around a billion times smaller than a metre.
Want the maths?
1 metre (m) ÷ 1000 = 1 millimetre (mm) ÷ 1000 = 1 micrometre (µm) ÷ 1000 = 1 nanometre (nm)
To put this into context;
• A typical bacteria cell is around 1000 nanometres in size
• The diameter of a human hair is about 80,000 nanometres
• An ant is millions of nanometres long
Lots of different terms are used in the scientific literature and the media when describing nanotechnology and nanomaterials: nanoparticles, nanoscience, nanotubes, nanoemulsions, nanosomes….the list goes on.
In general, a nanomaterial is a material with individual parts or dimensions on the nano-scale.
Despite all the new words and definitions, materials science at the nano-scale is not a new concept. Yes, there is exciting work being done building new structures and materials at this scale, for example through the manipulation of atoms and molecules, but the term "nanomaterial" can actually cover a huge array of materials, many of which we would not normally consider to be particularly revolutionary.
Nanomaterials have always existed, e.g. milk is an example of a nano-emulsion in which tiny droplets of fat are suspended in water, and ricotta cheese consists essentially of nanoparticles of milk proteins. Nanoparticles are actually much larger than molecules, which are the 'building blocks' of all matter.
Nature is full of nanomaterials and nano-structures. Nanoparticles and nanostructures of many different metals are naturally occurring in the environment .
For further information and for more examples of nano in the natural world, see the video "The strange new world of Nanoscience" narrated by Stephen Fry and produced in association with Cambridge University.
Certain ingredients used in cosmetics can now be defined as nanomaterials. These ingredients have been safely used for many years, but only now are they thought of as being "nanomaterials".
One of the most commonly used nanomaterials is titanium dioxide. Titanium dioxide is a mineral that is present in our natural environment. It is milled, or can be synthesised, to produce particles on the micro-scale, or smaller on the nano-scale. Nano-titanium dioxide also exists in nature.
Titanium dioxide is used in sunscreens to reflect and scatter UV light. Not only does it protect the skin from UV light extremely well, the nano-form also has the added benefits in the formulation of being easier to spread and also appearing transparent - so reducing whiteness. These are important benefits as the feel and look of a product on the skin can be a major factor in someone's decision to protect themselves from the sun using sunscreen.
Carbon black, an intense cosmetic colorant, can be used in the nano-form and is a good example of how reducing the pigment particle-size can alter the strength and opacity of colour.
Nanoparticles of other mineral materials may also be used in cosmetics.
It should be remembered that these materials can be available in different particle sizes. Only those sized 1 to 100nm are nanomaterials.
The actual legal definition of a "nanomaterial" has been the subject of much discussion. For the purposes of cosmetics a nanomaterial is defined under the UK cosmetics law as: "…an insoluble or biopersistant and intentionally manufactured material with one or more external dimensions, or an internal structure, on the scale from 1 to 100 nm".
What about nanoemulsions and nanosomes?
Nanoemulsions are not new: milk is an example of a nano-emulsion in which tiny droplets of fat are suspended in water. Nanoemulsions in cosmetics are very small droplets of oil and water that can increase the nutritious oil content of products such as moisturisers, without making the formula too thick or sticky. Some other products, for example some high performance moisturisers may employ tiny pocket-like structures called nanosomes (sometimes called liposomes) to help protect fragile ingredients from degrading. Nanoemulsions and nanosomes disintegrate upon application to the skin, releasing their contents onto the outer skin layer. As nanoemulsions and nanosomes are soluble and break down upon application to the skin, they are not included in the legal definition of a nanomaterial for cosmetics.
Public debate on nanotechnology has raised questions about the potential hazards to the environment and human health. It is claimed that as the particles of a material get smaller, their characteristics and properties might begin to differ from the larger particles of the same material. This may or may not be the case for different materials, and, if it is the case, it may or may not have an impact on safety. It is important to consider each material on a case-by-case basis and not to bunch all nanomaterials together as "potentially unsafe".
All cosmetic products must be safe to use. We can be confident in this because there are strict European safety laws that cover their manufacture and import. A major requirement of the cosmetic laws is that every product must undergo a safety assessment before it can be made available for sale. So if a nanomaterial is used as an ingredient, its presence and safety has to be assured before it can be placed on the UK market. All of this information is available to national enforcement agencies; in the UK that means Trading Standards.
A lot is known about the nanomaterials used in cosmetics. Take titanium dioxide as an example; it is actually one of the most widely studied materials of all time.
Also, the technology, and its safe use in consumer products, is constantly under review by regulatory bodies worldwide.
We are aware that concern has been expressed about the possible penetration of nanoparticles through the skin. In practice, cosmetic products are carefully formulated to ensure ingredients are delivered to the appropriate site on the skin or on the hair. The skin is a barrier, not a sieve; it is effective against penetration which is why even today most medicines have to be swallowed or injected and very few can be absorbed through the skin from topical patches. It is also good to remember that nanoparticles are actually much larger than molecules, the individual building blocks of all substances. Indeed a number of scientific studies have consistently shown that nanoparticles in current cosmetic use do not penetrate through human skin, even in cases when the skin is damaged.
In May 2011 the Nanodermatology Society issued a position statement on sunscreens, explaining the current knowledge on the skin penetration of nanomaterials. The statement is available here.
A new way of labelling is being introduced so that if an ingredient name is followed by the word "nano" in brackets it means that this ingredient is classed as a nanomaterial, i.e. it fits the definition provided in the EU cosmetics law. So, in the future, you will be able to tell if a cosmetic product contains a nanomaterial ingredient by looking at the ingredients list.
This means you will have even more information about the product you want to buy. The cosmetics industry is committed to providing consumers with this extra information, without implying any concern, with confidence in the safety of each product, which undergoes a complete safety review and evaluation before it can be placed on the market.
You may see an ingredient in the list that you have heard is a nanomaterial but is not listed with the "(nano)" suffix. It is important to remember that some ingredients that are used in the nano form can also be used in a non-nano form. For example, larger particles of titanium dioxide, which would not be labelled "(nano)", can also be used as a UV filter and as a white colorant.
The European Commission has a specific page on nanomaterials in cosmetics on its Consumer Affairs website here.
There is also a specific section of the European Commission's website on nanotechnology.
If you are looking for more information on nanotechnology and its uses in general, as well as the many issues being debated within this huge area of science, www.guardian.co.uk has a whole area on its website dedicated to nanotechnology: http://www.guardian.co.uk/science/nanotechnology
For further information and for examples of nano in the natural world, see the video "The strange new world of Nanoscience" narrated by Stephen Fry and produced in association with Cambridge University.
 Opinion of the scientific committee on cosmetic products and non-food products intended for consumers concerning titanium dioxide (SCCNFP/0005/98), adopted by the SCCNFP during the 14th plenary meeting of 24 October 2000.