Within our department several project are conduct where different types of human skin equivalents are used. Depending on the research questions the following skin models can be engineered: Leiden Epidermal model (LEM), the Full-Thickness model (FTM) and the Fibroblasts-Derived Matrix model FDM). 1) LEM consists of keratinocytes seeded on a non-cellular matrix (e.g. inert filter membrane or de-epidermized dermis. These epidermal models are suitable for e.g. corrosivity, irritation, or penetration tests. 2) FTM consists of keratinocytes, melanocytes and a fibroblast-populated three-dimensional collagen matrix. This model closely resembles native human skin. This full-thickness skin model can be used for tests, predictive screening and research on for example wound healing that requires the complexity of human skin, i.e. where the interaction between epidermal and dermal cells is crucial. 3) FDM is similar to the FTM model, but the dermal compartment consists of human fibroblast-derived extracellular matrix. This model can be used as a tool to evaluate the effect of e.g. ingredients on dermal processes. All three types can be used for predictive screening or contract research that requires the complexity of human skin. Variations of these models can be generated by incorporation of other cell types (e.g. endothelial cells). Models can also be grown at different humidity and oxygen concentrations.
Figure 1: Different types of skin models