title: Qualitative detection of single submicron and nanoparticles in human skin by scanning transmission x-ray microscopy.
abstract: First results on single particle detection in human skin samples by x-ray microscopy are reported. 94+/-6 and 161+/-13 nm gold core particles with silica shells and 298+/-11 nm silica particles coated with a gold shell on ultramicrotome sections of human skin were determined. The particles were applied on fresh intact skin samples, which were sectioned prior to imaging. After screening the sections by conventional microscopy techniques, defined areas of interest were qualitatively investigated by scanning transmission x-ray microscopy at the Swiss Light Source. In studies on the percutaneous penetration of 161+/-13 nm particles on human skin samples, x-ray microscopy yielded high-resolution images of single particles spreading on the superficial layer of the stratum corneum and on the epithelium in superficial parts of hair follicles. No deeper penetration was observed. The present work using x-ray microscopy provides the unique opportunity to study qualitative penetration processes and membrane-particle interactions on the level of single particles. This goes beyond present approaches using optical microscopy. Further improvement of this approach will allow one to study particles with different physicochemical properties and surface modifications, including responses of the exposed tissue.
authors.affiliation: Freie Universitat Berlin, Physikalische und Theoretische Chemie, Takustr. 3, 14195 Berlin, Germany. cmgraf@chemie.fu-berlin.de
authors.forename: Christina
authors.initials: C
authors.lastname: Graf
authors.forename: Martina
authors.initials: M
authors.lastname: Meinke
authors.forename: Qi
authors.initials: Q
authors.lastname: Gao
authors.forename: Sabrina
authors.initials: S
authors.lastname: Hadam
authors.forename: Jörg
authors.initials: J
authors.lastname: Raabe
authors.forename: Wolfram
authors.initials: W
authors.lastname: Sterry
authors.forename: Ulrike
authors.initials: U
authors.lastname: Blume-Peytavi
authors.forename: Jürgen
authors.initials: J
authors.lastname: Lademann
authors.forename: Eckart
authors.initials: E
authors.lastname: Rühl
authors.forename: Annika
authors.initials: A
authors.lastname: Vogt
mesh_terms: D006046:Gold / Q000032:analysis*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D017348:Microscopy, Electron, Scanning Transmission / Q000379:methods*; D053758:Nanoparticles / Q000648:ultrastructure*; D012867:Skin / Q000648:ultrastructure*
chemical_list: D006046:Gold