By Will Soutter
Nanomaterials in Cosmetics
Health Concerns over
Nanoparticles in Cosmetics
References and Further Reading
Figure 1. Nanoparticles are now used
in the vast majority of sunscreen products on the market, as well as
many other cosmetic products. Image credit: Photos.com.
Nanoparticles and other nanostructured materials have unique
properties which cannot be achieved when working with the bulk form of
the material. Applications for these special properties have been
suggested in many industries - the cosmetics industry is one of those
most eager to make the most of the opportunities presented by
Nanomaterials have been used to try and improve the performance of a wide
range of products, from moisturiser and anti-ageing creams to hair
care. Most of the main cosmetics manufacturers have at least some
"nano-enhanced" products in their range. However, there is still some
controversy over the safety of these novel materials, and the
regulation of nanomaterials in cosmetics is lax or unclear in many
parts of the world.
Nanomaterials in Cosmetics
The two main uses for nanoparticles in cosmetic products are UV
filtering and delivery of active ingredients.
Titanium dioxide and zinc oxide are both used extensively in
sunscreens to prevent UV damage to the skin - the nanoformulations of
these materials have been shown repeatedly to give much better
performance than larger particles, reflecting visible light and
absorbing UV with very high efficiency.
A wide range of nanostructures have been proposed as delivery
mechanisms for cosmetic ingredients in moisturisers, anti-ageing
creams, and other skincare products - from lipid nanoparticles to
dendritic or hyperbranched polymers. Again, these nanostructured
materials show much more efficient delivery of the active ingredient to
the skin cells.
Lipid nanoparticles are particularly effective, as they can merge
with the lipid bilayer in cell membranes, facilitating the delivery of
compounds which would otherwise not be able to enter the cell.
Lipid nanostructures, and dendritic biopolymers, provide the
additional benefit of being totally non-toxic and biocompatible. This
is in contrast to the metal and metal oxide nanoparticles - there are
still doubts about their safety for dermal use.
Figure 2. This video by
Project Beauty outlines the applications of nanotechnology in cosmetic
over Nanoparticles in Cosmetics
The size-dependent properties which enable nanomaterials to perform
so much better than their bulk counterparts can also potentially create negative effects
- their novel physical and chemical properties may alter the toxicity of
the materials in ways we do not yet fully understand. This has limited
the adoption of nanomaterials in many industry sectors, despite their
enhanced performance - this is a particularly crucial issue in
cosmetics, as the products are designed to be applied directly to human
In July 2012, materials supplier Antaria came under fire from environmental groups for
providing metal oxide powders containing nanoparticles for a number of
sunscreen brands which were advertised as nanoparticle-free. This
highlights the issue with classification of nano-enhanced products -
the particle size distribution of many powders will include some
nanoscale particles, and it is not clear how much this affects the
health implications of nanomaterials.
Nanoparticle-containing sunscreens have come under scrutiny
recently. Although research on the topic is still limited, some initial
results indicate that the UV-absorbing properties of TiO2
and ZnO2 could also catalyse the production of free radicals,
which could potentially lead to increased risk of cell damage and skin cancer.
This makes quantifying this effect very difficult, as skin cancer can also be caused by UV damage, which the nanoparticles protect against.
Some studies have also shown metal oxide nanoparticles passing through the
skin into the bloodstream - the effects of long-term exposure to
nanoparticles in the bloodstream has not yet been conclusively
Whether nano-enhanced sunscreens and other cosmetics turn out to
pose a significant health risk or not, the negative publicity given to
nanotechnology as a result of this issue are likely to affect consumer
acceptance of nanomaterials well into the future, even when their
effects are better understood - not just in cosmetics, but in many
other industries as well.
Figure 3. This report from
Today Tonight showcases the potential dangers associated with titanium
dioxide and zinc oxide nanoparticles in sunscreen.
Regulatory and legislative bodies around the world are beginning to
introduce clearer rules about nanotechnology. This is a very difficult
task, however, when the research is complicated and incomplete, as it
is for nanotoxicology. Lots more work is underway to better understand
the longer-term impact of nanomaterials on human health.
In the meantime, cosmetics manufacturers are developing more and
more nanoformulated products. Nanoemulsions and nanocrystals are
becoming more and more popular in skincare products, and they are
usually made of organic materials with very few toxicological issues.
Whatever the outcome of the current controversies, it seems highly
likely that nanomaterials will feature heavily in the future of the
References and Further