Quantum Dots unrepresentative of sunscreen formulations – NIA publishes full comments on controversial skin penetration study
The Nanotechnology Industries Association released comments on a recent publication, which used a semiconductor quantum dot nanoparticle (QD) model system, in order to examine the impact of UV-radiation (UVR) on nanoparticle skin penetration.
The Association reacted to the paper by delivering a number of facts on the benefits of sunscreens utilising mineral UV-filters, such as TiO2 or ZnO, as well as the significant differences between the TiO2- and ZnO-pigments used in sunscreen formulations and the much smaller semiconductor quantum dots, applied in the study.
The Association’s press release highlights that:
- Skin barrier properties are lower in mice compared to humans, due to structural differences including thinner stratum corneum in mice.
- The size of QDs reported in this paper (20-30 nm) corresponds to the hydrodynamic diameter, not the actual "physical" diameter (5 nm). In sunscreens, however, individual nanoparticles aggregate and agglomerate to form much larger units, which are typically > 100 nm.
- The paper clarifies that, even after UV-irradiation, skin penetration was minute, with most of the QDs found in the hair follicles and skin folds as expected.
- In summary, although the study provides insights into how UVR and nanoparticles might interact on the skin, its results can not be interpreted as applying to sunscreens that utilize TiO2 and ZnO pigments in their formulations.
Follow these links to find out more about the QD study, or to read the full NIA comment.
Related Links:
In its latest scientific assessment of nearly 1000 name-brand sunscreen, researchers Environmental Working Group (EWG), a US-based NGO, conclude ‘that zinc and titanium-based formulations are among the safest, most effective sunscreens on the market based on available evidence’. (1st July 2008)
The June issue of the journal Skin Pharmacology and Physiology features a paper that clarifies that ‘the current evidence suggests that nano-sized cosmetic or sunscreen ingredients pose no potential risk to human health, whereas their use in sunscreens has large benefits, such as the protection of human skin against skin cancer.’ (1st June 2008)
In response to the publication of the Friends of the Earth (FoE) report on Nanotechnology & Sunscreens, a paper entitled 'Rhetorical gamesmanship in the nano debates over sunscreens and nanoparticles' identifies that the FoE report uses a ‘risk profile shift’ from raw nanoparticles to sunscreen formulations to suggest environmental health and safety claims. (March 2008)
EU Project provides 1st evidence: ‘TiO2 nanoparticles do not penetrate through the intact skin’
This month's issue of Experimental Dermatology features a publication of the results of the NANODERM Project; the study reports the ‘first evidence that TiO2 nanoparticles in vivo do not penetrate through the intact epidermal barrier.’ (February 2008)
This month's issue of Experimental Dermatology features a publication of the results of the NANODERM Project; the study reports the ‘first evidence that TiO2 nanoparticles in vivo do not penetrate through the intact epidermal barrier.’ (February 2008)