Abstract
Titanium dioxide (TiO2) nanoparticles are extensively used today in sunscreens and coatings as protective compounds for human skin and material surfaces from UV radiation. In this paper, such particles are investigated by electron paramagnetic resonance spectroscopy as sources of free radicals under UV irradiation. The surface density of a placebo with embedded particles corresponds to the recommendations of dermatologists (2 mg cm-2). It is revealed that if applied onto glass, small particles 25 nm in diameter produce an increased amount of free radicals compared to the larger ones of 400 nm diam and the placebo itself. However, if applied onto porcine skin in vitro, there is no statistically distinct difference in the amount of radicals generated by the two kinds of particles on skin and by the skin itself. This proves that although particles as part of sunscreens produce free radicals, the effect is negligible in comparison to the production of radicals by skin in vitro.
| Original language | English |
|---|---|
| Article number | 021011 |
| Journal | Journal of Biomedical Optics |
| Volume | 14 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - 19 Mar 2009 |
| MoE publication type | A1 Journal article-refereed |
Funding
The authors thank Dr. Maxim Darvin for his assistance during the experiments and Dr. Elena Zagainova from Nizhny Novgorod Medical Academy (Russia) for the TEM photos of the particles. A.P.P. thanks Infotech Oulu and the Tauno Tönning Foundation (both Finland) and DAAD (Germany) for support of this study. This work was partially supported by the RFBR Grant No. 07-02-01000.
Keywords
- Free radicals
- Nanoparticles
- Phototoxicity
- Porcine skin
- Titanium dioxide
- Ultraviolet light