Adapted from (Löwa et al., 2018).
According to the type of layer from the human skin that each model can
mimic, two main types of reconstructed skin models are described:
reconstructed human epidermis (RHE) models which mimic the epidermis and
the living skin equivalents (LSEs) which aim to simulate the full human
skin (Kuchler et al., 2013, Flaten et al., 2015, Randall et al., 2018).
Nowadays, there are some commercially available models of the human
epidermis (EpiSkin®, EpiDerm®,
SkinEthic®) or full thickness skin
(Phenion®) (Van Gele et al., 2011, Netzlaff et al.,
2005).
The construction of the more complex 3D models usually include
fibroblasts cultures which are embedded in a 3D matrix to mimic the
dermis layer; then, keratinocytes can be seeded on top of the latter
layer to simulate the epidermis. An air-liquid interface is established
in order to allow the differentiation keratinocytes and formation of the
different epidermal sublayers. The artificial matrix may include in
their composition collagen or fibrin fibbers or even alginate and
chitosan or different synthetic polymers (reviewed in (Sarkiri et al.,
2019, Yu et al., 2019)).
Skin engineered substitutes may be used not only as alternatives toex vivo and in vitro non-cell-based models for testing
drugs in healthy or pathological conditions but they can also be applied
in patients for regeneration of damaged skin (reviewed in (Yu et al.,
2019)). A diagram summarizing the different applications of skin
engineered substitutes is depicted in Figure 4.