title: Study on penetration of titanium dioxide (TiO(2)) nanoparticles into intact and damaged skin in vitro.
abstract: It is important for toxicological assessment of nanoparticles to determine the penetration of nanoparticle in skin qualitatively and quantitatively. Skin penetration of four different types of rutile titanium dioxide (TiO(2)) (T-35, 35 nm, non-coating; TC-35, 35 nm, with almina/silica/silicon coating; T-disp, 10 x 100 nm, mixture of almina coated and silicon coated particles, dispersed in cyclopentasiloxan; T-250, 250 nm, non-coating) was determined with in vitro intact, stripped, and hair-removed skin of Yucatan micropigs to study the effect of dispersion and skin conditions. The TiO(2) was suspended in a volatile silicone fluid used for cosmetics, cyclopentasiloxane, at a concentration of 10%. The suspension was applied at a dose 2 microl/cm(2) for 24 hr, followed by cyanoacrylate stripping. The Ti concentration in skin was determined by ICP-MS. T-35 and T-250 easily aggregated in suspension with a mean diameter greater than 1 microm. TC-35 and T-disp showed good dispersion properties with a mean diameter in suspension of approximately 100 nm. No penetration was observed regardless of TiO(2) type in intact and stripped skin. The concentration of Ti in skin was significantly higher when TC-35 was applied on hair-removed skin. SEM-EDS observation showed that Ti penetrated into vacant hair follicles (greater than 1 mm below the skin surface), however, it did not penetrate into dermis or viable epidermis.
authors.forename: Mika
authors.initials: M
authors.lastname: Senzui
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Tamura
authors.forename: Keiko
authors.initials: K
authors.lastname: Miura
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Ikarashi
authors.forename: Yoshiteru
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Makiko
authors.initials: M
authors.lastname: Fujii
mesh_terms: D000818:Animals; D015194:Diffusion Chambers, Culture; D066298:In Vitro Techniques; D053768:Metal Nanoparticles / Q000008:administration & dosage* / Q000648:ultrastructure; D010316:Particle Size; D012867:Skin / Q000187:drug effects* / Q000293:injuries / Q000378:metabolism; D012869:Skin Absorption / Q000187:drug effects* / Q000502:physiology; D013473:Sunscreening Agents / Q000032:analysis / Q000378:metabolism / Q000493:pharmacokinetics*; D013552:Swine; D013556:Swine, Miniature; D014025:Titanium / Q000032:analysis / Q000378:metabolism / Q000493:pharmacokinetics*
chemical_list: D013473:Sunscreening Agents; C009495:titanium dioxide; D014025:Titanium