title: Zinc oxide nanoparticle removal from wounded human skin.
abstract: OBJECTIVE
  Nanoparticle removal from skin is relevant given the concern over topical nanoparticle toxicity. Zinc oxide nanoparticles (ZnO-NPs) are commonly used in sunscreens and their use is currently debated. This study explores the penetration and removal of ZnO-NPs from injured skin.
  
  
  METHODS
  Ex vivo/in vivo human skin was tape-stripped and/or microneedled followed by ZnO-NP application. After 2 h, treated skin was washed three-times using soapy water. Multiphoton tomography assessed the ZnO-NP signal before and after washing.
  
  
  RESULTS
  Washing once removed over 85 and 83% of ZnO-NP signal from ex vivo intact and tape-stripped skin, respectively (p < 0.05) but only 28% (p = 0.5) was removed from puncture sites. A similar trend was found in vivo with removal of 85 and 93% of ZnO-NP signal from intact and tape-stripped skin, respectively (p < 0.05).
  
  
  CONCLUSIONS
  Washing is effective for the removal of ZnO-NPs from superficial layers of intact and tape-stripped skin, but not from puncture wounds.
authors: Dermatology Research Centre, The University of Queensland, Brisbane, Australia.
authors: Anthony P
authors: AP
authors: Raphael
authors: Daniel
authors: D
authors: Sundh
authors: Jeffrey E
authors: JE
authors: Grice
authors: Michael S
authors: MS
authors: Roberts
authors: H Peter
authors: HP
authors: Soyer
authors: Tarl W
authors: TW
authors: Prow
mesh_terms: D006801:Humans; D066298:In Vitro Techniques; D053768:Metal Nanoparticles / Q000737:chemistry*; D012867:Skin / Q000737:chemistry*; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D015034:Zinc Oxide