The EpiSkin models are obtained by culturing adult human keratinocytes on a collagen base in conditions which permit their terminal differentiation and the reconstruction of an epidermis with a functional horny layer.

The human keratinocytes come from mammary/abdominal samples obtained from healthy consenting donors during plastic surgery. HIV 1 & 2, HEP B and HEP C tests are carried out on the donors as well as verification of the bacteriological and fungal sterility of the cells.

The production of EpiSkin (0.38 cm² and 1.07 cm²) is in accordance with the quality reference norms ISO 9001, ensuring traceability and reproducibility of the epidermal tissue as well as that of the quality control tests carried out on each batch of epidermis.

The reproducibility of each batch is checked by histological analysis taking into account the general organisation, the stratification of the epidermis, the nucleation of the basal layer and the size of the intercellular spaces, adhesion of the basal

layer to the support and the quantity of granular cells and the thickness of the horny layer. Each criterion is scored out of 4. The maximum score is 28. The minimum score for the criterion of acceptability of the model is 19.

The reproducibility of the response of each EpiSkin batch is tested against a reference irritant: SDS. The IC50 of the surfactant is measured by the MTT assay after 18 hours of contact. The minimum score for acceptability of the model is 1mg/ml.