title: Skin corrosion and irritation test of sunscreen nanoparticles using reconstructed 3D human skin model.
abstract: OBJECTIVE
  Effects of nanoparticles including zinc oxide nanoparticles, titanium oxide nanoparticles, and their mixtures on skin corrosion and irritation were investigated by using in vitro 3D human skin models (KeraSkin ((TM)) ) and the results were compared to those of an in vivo animal test.
  
  
  METHODS
  Skin models were incubated with nanoparticles for a definite time period and cell viability was measured by the 3-(4, 5-dimethylthiazol-2-yl)-2.5-diphenyltetrazolium bromide method. Skin corrosion and irritation were identified by the decreased viability based on the pre-determined threshold.
  
  
  RESULTS
  Cell viability after exposure to nanomaterial was not decreased to the pre-determined threshold level, which was 15% after 60 minutes exposure in corrosion test and 50% after 45 minutes exposure in the irritation test. IL-1α release and histopathological findings support the results of cell viability test. In vivo test using rabbits also showed non-corrosive and non-irritant results.
  
  
  CONCLUSIONS
  The findings provide the evidence that zinc oxide nanoparticles, titanium oxide nanoparticles and their mixture are 'non corrosive' and 'non-irritant' to the human skin by a globally harmonized classification system. In vivo test using animals can be replaced by an alternative in vitro test.
authors.affiliation: College of Pharmacy, Dongduk Women's University, Seoul, Korea.
authors.forename: Jonghye
authors.initials: J
authors.lastname: Choi
authors.affiliation: College of Pharmacy, Dongduk Women's University, Seoul, Korea.
authors.forename: Hyejin
authors.initials: H
authors.lastname: Kim
authors.affiliation: School of Environmental Engineering, University of Seoul, Seoul, Korea.
authors.forename: Jinhee
authors.initials: J
authors.lastname: Choi
authors.affiliation: Fusion Technology Laboratory, Hoseo University, Asan, Seoul, Korea.
authors.forename: Seung Min
authors.initials: SM
authors.lastname: Oh
authors.affiliation: Korea Environmental Institute, Seoul, Korea.
authors.forename: Jeonggue
authors.initials: J
authors.lastname: Park
authors.affiliation: College of Pharmacy, Dongduk Women's University, Seoul, Korea.
authors.forename: Kwangsik
authors.initials: K
authors.lastname: Park
keywords: 3D skin model; Alternative methods; Corrosion; Irritation; Nanoparticles