Das Projekt "Quality of skin as a barrier to ultra-fine particles (NANODERM)" wird vom Umweltbundesamt gefördert und von Universität Leipzig, Fakultät für Physik und Geowissenschaften durchgeführt. Objective: Today' s population is increasingly exposed to ultrafine particles (less than 20 nm; e.g. Aerosil, TiO2) contained in body care and household products. Tape stripping studies and recent ion microscopy pilot studies revealed that such particles in, liposomal formulations penetrate the horny layer with large concentrations at the stratum granulosum and the possible risk of further penetration into vital tissue, especially for skin with an impaired barrier function. Here, apart from electron microscopy, high-resolution ion-microscopy techniques will be employed on skin cross-sections from biopsies (pig, human), which yield elemental maps of both the epidermis and dermis with ppm sensitivity for Ti or higher sensitivity with radiotracers (labelled TiO2) on pig skin. Pathways for percutaneous uptake and clearance will be studied. If such particles penetrate into the dermis, in-situ studies of tissue and in-vitro studies of particle-cell interactions follows.