title: Modified TiO(2) particles differentially affect human skin fibroblasts exposed to UVA light.
abstract: Numerous sunscreens contain titanium dioxide (TiO(2)) because of its ability to reflect, scatter, and absorb UV radiation, thus preventing sunlight-related skin disorders. Since TiO(2) is well known to generate reactive oxygen species (ROS) under photoexcitation, it is chemically modified when used in sunscreens. In the present study, five modified TiO(2) particles, specifically developed and marketed for sunscreens, were tested using different in vitro models, including cultured human skin fibroblasts (HuDe), to investigate their possible photocatalytic effects following UVA exposure. The results obtained show that the type of modification and crystal form determine their ability to (a) induce photobleaching of the DPPH radical, (b) photodegrade deoxyribose, (c) reduce cell viability, (d) increase/decrease DNA damage, and (e) increase/decrease intracellular ROS. This research concludes that some modified TiO(2) particles still retain photocatalytic activity under the experimental conditions employed, especially those in which the anatase crystal form of TiO(2) is present. The penetration of TiO(2) nanosized particles into the viable epidermis of skin is still under debate; thus, the results presented here contribute to gaining further knowledge on the potential effects of TiO(2) particles at the cellular level, in the worst possible case that they do penetrate.
authors.affiliation: Dipartimento di Biochimica, Biologia e Genetica, , Università Politecnica delle Marche, I-60131 Ancona, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Tiano
authors.forename: Tatiana
authors.initials: T
authors.lastname: Armeni
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Venditti
authors.forename: Gianni
authors.initials: G
authors.lastname: Barucca
authors.forename: Laura
authors.initials: L
authors.lastname: Mincarelli
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Damiani
mesh_terms: D001713:Biphenyl Compounds / Q000737:chemistry; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D002478:Cells, Cultured; D004249:DNA Damage / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects* / Q000528:radiation effects*; D006801:Humans; D053758:Nanoparticles; D055668:Photochemical Processes; D010851:Picrates / Q000737:chemistry; D013473:Sunscreening Agents / Q000494:pharmacology; D014025:Titanium / Q000009:adverse effects / Q000737:chemistry / Q000494:pharmacology* / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D001713:Biphenyl Compounds; D010851:Picrates; D013473:Sunscreening Agents; C009495:titanium dioxide; D014025:Titanium; C004931:1,1-diphenyl-2-picrylhydrazyl