Nanotechnology has infiltrated our lives in many forms from the silver in our deodorant as an anti-microbial agent to zinc oxide and titanium dioxide as strong absorption materials of ultra-violet light in our sunscreens. In order to understand how they will affect our lives, it is important to understand what they are.
The word ‘nano’ essentially refers to the size of the particles that are used in the product. A nanometre is 1 billionth of a meter. To put that size into some context, that’s around 80,000 times smaller than the width of a human hair. The compounds must be present in a size range of 1 to 100 nanometres in order to warrant that description. These nanomaterials can also be natural or manmade.
The public perception is that these molecules have been a recent discovery but they in fact have been is use for centuries, without our knowledge. Stained glass used in famous cathedrals such as Notre Dame de Paris dates back to around the 12th century and there are even examples of the use of nanoparticles that date back to the 4th century. The rich colours are attributed to nanoparticles of gold and other metal oxides and metal chlorides.
What would be considered new, is our ability to control and manipulate atoms through breakthroughs in synthetic chemistry and analytical technology. This means that we can design, create and characterize nanomaterials like never before.
So how does this affect me?
Manufactures of textiles, clothes and personal care products are now looking at nanotechnology to not only gain a marketing advantage over their competitors but also to improve the functionality of their products. The reason why cosmetic manufactures in particular are using nanoparticles of titanium dioxide and zinc oxide in their sunscreen is due to their inherently smaller size they can penetrate deeper into the layers of the skin. This will protect us longer and more effectively from harmful UV radiation from the sun which in turn will reduce our risk of skin cancer.
Size matters…
It certainly does, especially when considering the particle size of these nanomaterials. The size of these particles will dictate not only their chemical properties but also how toxic they could be to human, animal and ecological health. Studies have shown that toxicity is mainly concerned with the production of reactive oxygen species, including free radicals which will result in oxidative stress, inflammation, and consequent damage to proteins, membranes and DNA. The smaller the particle size, the easier that these nanoparticles can gain access to the blood stream via skin or inhalation and from there they will be transported to the various organs. 500 nm titanium dioxide particles have only a small ability to cause DNA strand breakage whereas 20 nm particles of titanium dioxide are capable of causing complete destruction of super-coiled DNA, even at low doses and in the absence of exposure to UV.
As European legislators hold their breath on how exactly to regulate these materials, we are currently in an interim period of consumer uncertainty regarding these weird and wonderful particles and materials. The cosmetic industry in Europe has taken the initiative by introducing a product labelling and registration protocol. The words “nano” must appear on the cosmetic products ingredient label after the ingredients name. The cosmetic product containing these nanomaterials must also be notified to the European Union 6 months before it is set to hit the market in the EU. Other industries may look to the cosmetic industry as an example of pro-active legislation designed to be cautious while maintaining and improving the health of our society.
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