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Crystalline phase modulates the potency of nanometric TiO2 to adhere and perturb the stratum corneum of porcine skin under indoor light
Link to Journal Abstract
Nanometric TiO2 is largely employed in cosmetics, but in vitro toxic effects have been reported when nano-TiO2 is exposed to UV light. The photoreactivity of TiO2 largely depends on its crystal phase, namely anatase and rutile. Surface acidity, also dependent on crystal structure, may impart a positive or negative charge to nanomaterial surface and ultimately modulate the particle adhesion to tissues. Three nanometric TiO2 powders with different crystal lattice and surface charge (anatase, rutile and anatase/rutile) have here been employed to investigate the interaction with skin and examine the molecular mechanisms of the TiO2-induced oxidative damage. The strength of the interaction of nano-TiO2 with skin has been revealed by chemiometric mapping (ì-XRF and SEM-EDS) after tissue washing. Positively charged anatase and anatase/rutile, but not negatively charged rutile, were strongly held on the skin surface and were able to promote a structural rearrangement of the lipid bilayer in the stratum corneum (DSC and Raman) under controlled indoor illumination (UVA < 1 mW/m2). Under the same conditions, cell-free reactivity tests (ROS-mediated free-radical release and lipoperoxidation) indicated that anatase and anatase/rutile are more reactive than rutile, suggesting a ROS-mediated oxidative mechanism that may alter the structure of the stratum corneum. Both the higher oxidative potential and the stronger adhesion to skin of anatase and anatase/rutile TiO2 may explain the stronger disorganization induced by these two samples and suggest the use of rutile to produce safer TiO2-based cosmetic and pharmaceutical products.
In this study, three nanometric TiO2 powders with different crystal lattice and surface charge (anatase, rutile and anatase/rutile) have here been employed to investigate the interaction with skin and examine the molecular mechanisms of the TiO2-induced oxidative damage.
Peer Reviewed Journal Article
Exposure Or Hazard Target
Method Of Study
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Chemical Research in Toxicology, 2013, Just Accepted Manus., DOI: 10.1021/tx400285j
Chemical Research in Toxicology
Turci F, Peira E, Corazzari I, Fenoglio I, Trotta M, Fubini B
Last updated on September 26, 2013
This work is supported in part by the Nanoscale Science and Engineering Initiative of the National Science Foundation
under NSF Award Number EEC-0118007.
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