Terri Vinson, cosmetic chemist and CEO of Synergie Skin, explains why nanoparticles are essential to the future of cosmetics.
Mineral makeup or physical (inorganic) sunscreens containing zinc oxide and titanium dioxide have received much press of late with consumers being warned about using products containing nanoparticles. Yet, I believe the humble nanoparticle is one of the most misunderstood entities in the cosmeceutical arena.
According to the Journal of Nanobiotechnology, nano-materials are at the leading edge of the rapidly developing field of nanotechnology. ‘Their unique size-dependent properties make these materials superior and indispensable in many areas of human activity,’ the journal reports. If you’re confused about their implications for the cosmetic industry, you are not alone. Before allowing scaremongers to cloud your judgement when choosing skincare products, the following information will help you to discern fact from hype.
Nanotechnology has revolutionised both the medical and cosmetic industry and should be respected as crucial to the advancement of scientific technology. It has enabled advancements in joint replacement with low rejection of artificial bone. It has also been used to minimise side effects for some cancer therapies and, by using nanoparticle tagging, it has allowed scientists to discover how different proteins in our cells interact. In my opinion, consumers have been misinformed and misled into believing that all nanoparticles are dangerous and toxic if applied topically. This is not the case. Rather, it is the particle or ingredient that is ‘nanophased’ (that is, made into nanoparticles) that may be dangerous and not the fact that a particle is nanophased in the first place.
What is a nanoparticle?
A nanoparticle is defined as a particle smaller in diameter than 100 nanometres. A particle of this size is able to penetrate human skin and interact with living cells. One nanometre represents one millionth of a millimetre. To put this into perspective, a human cell is about 10,000 nanometres in diameter, or about 100 times bigger than the largest nanoparticle.
It is important to realise that nanotechnology does not define the chemical characteristics of the particle – it merely defines its size. For example, nanoparticles of a toxic chemical such as lead or arsenic would be fatal if inhaled or applied to the skin in a sufficiently large dose. Conversely, nanoparticles delivering asthma medication via an inhaler would be life-saving to an asthmatic. Often, therefore, the ingredient or drug that has been nano phased may be vital for the wellbeing of the recipient.
Sunscreen and nanoparticles
As a scientist, I believe there is no toxicity associated in applying nanoparticles of zinc oxide topically as a sun protection or anti-inflammatory skin product. Research shows that zinc oxide particles over 30 nanometres, when applied topically, do not enter the bloodstream and present no threat to human health. Research suggesting otherwise considers doses that could not be achieved with normal topical application on viable human skin.
Titanium dioxide nanoparticles, however, have been reported to induce free radical damage to living cells at low doses. In my opinion, therefore, when formulating with titanium dioxide, particles should not be nanosized to ensure they do not penetrate the outer stratum corneum and therefore avoid contact with living cells in the dermis.
Unfortunately, larger particle size titanium dioxide may exhibit a whitening effect on the skin that is often undesirable for many consumers with darker skin tones. Many mineral makeup formulators choose to incorporate large particle titanium dioxide with zinc oxide to enhance the UV protection of their products. Logically, mineral makeup should not contain any nanoparticles. The particles should be large and opaque. After all, the primary function of makeup is to cover imperfections and not be invisible on the skin. The large, ‘macro-sized’ zinc oxide and titanium dioxide particles in mineral makeup are designed to create physical coverage on the skin, both as UV protection and for cosmetic coverage. If you are concerned, the makeup manufacturer will be able to give you information about the type and size of particles they incorporate into their products.
Nanotechnology in cosmetic science
In the rapidly evolving field of cosmetic science, nanotechnology is successfully used to enable enhanced delivery of active ingredients to target skin cells. Peptide technology is a prime example of nanoparticles of active ingredients being used to improve skin health.
Peptides are tiny pieces of protein that are small enough (nanophased) to penetrate the outer skin layers. Peptides themselves are extremely effective nanoparticles that are able to perform specific beneficial effects. They exhibit a plethora of biological effects on cells such as stimulating collagen, reducing pigmentation and regulating oil production.
Growth factors are also examples of nanoparticles. However, I have serious reservations regarding topical application of growth factors due to their potential for stimulating proliferation of malignant cells. There is still much research to be done on applying these nanoparticles to the skin and I choose not to formulate with growth factors.
Ultimately, consumers need to be aware that a ‘nanoparticle’ is simply a description of the size of the particle, and that it’s the particle itself that can be either beneficial or harmful. Nanoparticles are to be embraced and not feared. It is this knowledge that enables us to allay fears and help consumers make informed decisions on skin care and sun protection.