Nanoparticles are increasingly being used in a variety of products in Canada. This can be seen in “stain-free” clothes, as well as foods, cosmetics, sunscreens and many other personal care products that we use everyday. Nanoparticles are particles smaller than 100 nanometres (nm), a nanometre is one billionths of a metre. To compare, the average thickness of the human hair is about 10,000 nm. Many assume that all nanoparticles are synthetic, however there are many that are naturally derived – whether they are extracts from plants or minerals from the environment. Nanoparticles are increasingly added to produce more effective cosmetic and drug products and are favoured for their high surface area and low volume ratio.
The large surface area allows nanoparticles to carry additional properties beyond those of the original material. This can also be both aesthetic and active purposes of a personal care product. For example, many sunscreen products use nano-zinc oxide (ZnO) or nano-titanium dioxide (TiO2) as active ingredients to create a transparent product. Nano-ZnO and TiO2 also increases its ability to reflect UV rays and thus increase SPF and efficacy of the sunscreen product, compared to their non-nano counterparts.
However, their very small sizes may allow them to be readily absorbed into the skin. This can cause nanoparticles to be very reactive and catalytic in the body due to their ability to penetrate cell membranes and interact with biological systems. Because the commercial uses of nanoparticles are relatively new, it is very early to determine the long-term health risks of these particles and there is not enough adequate research that demonstrates the current absorption of some nanoparticles within the blood.
In addition, a major issue with nanoparticles in personal care products is the lack of differentiating nanoparticles with their larger counterparts by regulatory bodies. Although microparticles, which are millionths of a metre, have been around for many decades and have been tested for safety and efficacy in a variety of products, nanoparticles have been on the rise recently and are being treated the same even though they are much smaller structures. In addition, these particles are present in many personal care products, however consumers are not aware of the presence of these compounds and thus cannot have a choice in what they want present on their body. Recent strides have increased transparency in the European Union as all “nano” ingredients in cosmetics are required to be labelled as evident in their REACH (Registration, Evaluation, Authorisation and Restriction of Chemical substances) legislation. Canada had added nano zinc oxide and nano titanium dioxide specifically as permitted ingredients in its sunscreen monograph.
Further research and time is required for us to completely understand the benefits and risks associated with nanoparticles. However, since many consumers may not be willing to accept these possible risks, further transparency is required to give the public a choice of what substances they want on their skin.