US EPA

155612 

Journal Article 

In vivo skin penetration of quantum dot nanoparticles in the murine model: The effect of UVR 

Mortensen, LJ; Oberdorster, G; Pentland, AP; Delouise, LA 

2008 

1 

Nano Letters
ISSN: 1530-6984
EISSN: 1530-6992 

8 

9 

2779-2787 

18687009 

10.1021/nl801323y 

WOS:000259140200031 

Ultraviolet radiation (UVR) has widespread effects on the biology and integrity of the skin barrier. Research on the mechanisms that drive
these changes, as well as their effect on skin barrier function, has been ongoing since the 1980s. However, no studies have examined the
impact of UVR on nanoparticle skin penetration. Nanoparticles (NP) are commonly used in sunscreens and other cosmetics, and since consumer
use of sunscreen is often applied to sun damaged skin, the effect of UVR on NP skin penetration is a concern due to potential toxicity. In this
study, we investigate NP skin penetration by employing an in vivo semiconductor quantum dot nanoparticle (QD) model system. This model
system improves NP imaging capabilities and provides additional primary interest due to widespread and expanding use of QD in research
applications and manufacturing. In our experiments, carboxylated QD were applied to the skin of SKH-1 mice in a glycerol vehicle with and
without UVR exposure. The skin collection and penetration patterns were evaluated 8 and 24 h after QD application using tissue histology,
confocal microscopy, and transmission electron microscopy (TEM) with EDAX analysis. Low levels of penetration were seen in both the
non-UVR exposed mice and the UVR exposed mice. Qualitatively higher levels of penetration were observable in the UVR exposed mice.
These results are the first for in vivo QD skin penetration, and provide important insight into the ability of QD to penetrate intact and UVR
compromised skin barrier. Our findings raise concern that NP of similar size and surface chemistry, such as metal oxide NP found in sunscreens,
may also penetrate UV damaged skin.