Our artificial skin model is composed of keratinocytes to form an epidermis, which is a fully stratified squamous epithelium and a dermis with fibroblasts that comprise collagen as well de novo synthesized extracellular matrix (ECM) thus building an excellent connective tissue. As skin is very often the site of first contact for chemicals, test compounds are applied on the surface of the skin model per standard operation procedure. Subsequently fibroblast and keratinocytes are isolated and subjected to the comet assay that allows the reliable identification of mutagens and clastogens.