Nanotechnology Industries Association Releases Comments on 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.

Click here to read the full NIA comment.