Nanotechnology and Sun Care A Risk Review
In the past few years, the use of nanomaterials in cosmetic products has been the cause of much debate, and has instigated a wide range of scientific studies. Large amounts of data have been considered in forming educated opinions on the safety of nanoparticles such as ‘nano’ versions of titanium dioxide (TiO2) and zinc oxide (ZnO) in sun care product manufacture. The vast majority of the data in the studies still recognises that ultrafine TiO2 and ZnO are safe for use in sun care applications, and offer excellent protection against UV radiation.
Recent published opinions have brought a final definition of nanomaterials in cosmetic products closer, though a number of areas require further clarification. This article aims to review the studies and publications which have led to the formation of the current definitions in Europe, and highlight areas such as experimental methodology which require further consideration if comparable results are to be reported.
Nanomaterials have been used in sun care products for nearly 30 years. Most of the examples of nanoparticles in such products come from the use of nano-TiO2 and ZnO, but ‘nano’ versions of other substances, such as iron oxides, silica and alumina are also found in cosmetic products. A simplified common definition of a nanomaterial is one which has dimensions of less than 100 nm, but as we will show, many aspects need to be considered in forming such definitions.
The use of ‘nano’ versions of substances such as TiO2 and ZnO in sun care products stems from their ability to attenuate UV radiation, while producing a transparent film on the skin which maintains the cosmetic elegance of the formulation. Mie theory (1) predicts the optical properties of inorganic particles, suggesting that particles below 100 nm are likely to have more aesthetically pleasing properties.
The use of nanotechnology in personal care has initiated a great deal of debate about the safety of its’ use, with concerns being raised about the potential for dermal absorption, inhalation and ingestion. The following sections will review some of the publ ...