title: Detecting free radicals in sunscreens exposed to UVA radiation using chemiluminescence.
abstract: One of the current concerns with the application of nanoparticles in sunscreens, and in particular nano-TiO2 and ZnO, is their potential to photogenerate free radicals and reactive oxygen species (ROS) when they absorb ultraviolet wavelengths from sunlight. Free radicals and ROS are known to be associated with UV-induced skin damage and oxidative stress, from which sunscreens are expected to offer significant protection. Here we describe a simple method, based on chemiluminescence emission, for detecting free radicals generated in commercial sunscreens alone, and when applied to various substrates, following exposure to UVA (320-400nm) radiation. This photo-induced chemiluminescence (PICL) technique could be used to optimise sunscreen formulations so as to minimise free radical photogeneration during exposure to sunlight.
authors.affiliation: CSIRO Advanced Materials TCP (Nanosafety), CSIRO Materials Science and Engineering, Geelong Technology Precinct, Deakin University, 75, Pigdons Road, Waurn Ponds, VIC 3216, Australia. Electronic address: keith.millington@csiro.au.
authors.forename: Keith R
authors.initials: KR
authors.lastname: Millington
authors.affiliation: CSIRO Advanced Materials TCP (Nanosafety), CSIRO Animal, Food and Health Sciences, North Ryde, NSW 2113, Australia.
authors.forename: Megan J
authors.initials: MJ
authors.lastname: Osmond
authors.affiliation: CSIRO Advanced Materials TCP (Nanosafety), CSIRO Animal, Food and Health Sciences, North Ryde, NSW 2113, Australia.
authors.forename: Maxine J
authors.initials: MJ
authors.lastname: McCall
mesh_terms: D000818:Animals; D002384:Catalysis; D005260:Female; D005609:Free Radicals / Q000032:analysis*; D008163:Luminescent Measurements; D053768:Metal Nanoparticles / Q000737:chemistry / Q000633:toxicity; D051379:Mice; D008812:Mice, Hairless; D012235:Rhodamines / Q000737:chemistry / Q000378:metabolism; D012867:Skin / Q000187:drug effects / Q000528:radiation effects; D013473:Sunscreening Agents / Q000737:chemistry* / Q000494:pharmacology; D014025:Titanium / Q000737:chemistry; D014466:Ultraviolet Rays; D015034:Zinc Oxide / Q000737:chemistry
chemical_list: D005609:Free Radicals; D012235:Rhodamines; D013473:Sunscreening Agents; C009495:titanium dioxide; D014025:Titanium; C029773:rhodamine B; D015034:Zinc Oxide
keywords: Chemiluminescence; Free radicals; Keratin; Nanoparticles; Photocatalysis; Skin; Sunscreen