title: Imaging and characterization of engineered nanoparticles in sunscreens by electron microscopy, under wet and dry conditions.
abstract: There is increasing concern over the risks of nanoparticles to humans and the environment, but little is known about the properties of the nanoparticulate mineral filters, such as titanium dioxide and zinc oxide, in sunscreens. There is an urgent need to develop methods for characterizing nanoparticles in (NPs) such products to provide data for human and environmental risk assessments. This study explored three methods (transmission electron microscopy [TEM], conventional scanning electron microscopy [SEM], and wet-scanning electron microscopy [WetSEM]) for characterizing NPs in sunscreens. Our results showed that these products contained titanium dioxide and zinc oxide particles in the nanometer range; thus, it is likely that consumers and the environment are exposed to engineered NPs through the use of these products. Further, we found that the combination of all three microscopy methods provided the most comprehensive information on size-related properties, which are crucial parameters for risk assessment of NPs in wet matrices.
authors.affiliation: Safety and Environmental Technology Group, Zürich, Switzerland.
authors.forename: Christiane
authors.initials: C
authors.lastname: Lorenz
authors.forename: Karen
authors.initials: K
authors.lastname: Tiede
authors.forename: Steven
authors.initials: S
authors.lastname: Tear
authors.forename: Alistair
authors.initials: A
authors.lastname: Boxall
authors.forename: Natalie
authors.initials: N
authors.lastname: Von Goetz
authors.forename: Konrad
authors.initials: K
authors.lastname: Hungerbühler
mesh_terms: D053768:Metal Nanoparticles / Q000737:chemistry*; D008854:Microscopy, Electron; D010316:Particle Size; D013473:Sunscreening Agents / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*; D014867:Water; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D013473:Sunscreening Agents; D014867:Water; C009495:titanium dioxide; D014025:Titanium; D015034:Zinc Oxide