Epidermal Skin Model (LEM)

Healthy Leiden epidermal skin model (LEM)

The healthy Leiden epidermal skin model (LEM) provides you with a healthy, living human epidermis on an inert acellular filter. Biomimiq’s LEMs can be used for a myriad of research and screening applications requiring only an epidermis, including toxicity, corrosivity and irritation testing. In addition, Biomimiq’s LEMs can be customized to answer your specific research questions. For example, LEMs can be infected with fungi or bacteria to study (treatment of) skin infections on human epidermis or LEMs can be generated with diseased epidermal keratinocytes of your choice.

Epidermal cell types

The Leiden epidermal skin model (LEM) is generated by culturing primary human keratinocytes air-exposed on an inert acellular filter.






Normalized stratification and proliferation

Like healthy human epidermis, Biomimiq’s epidermal skin models consist of about eight epidermal cell layers. The epidermis displays normal stratification into a basal layer (stratum basale), spinous layer (stratum spinosum), granular layer (stratum granulosum) and outer corneal layer (stratum corneum). Proliferation rates in Biomimiq’s Leiden epidermal model (LEM) are normalized in vitro: approximately 15% of the basal epidermal cells are in a proliferative state.

Epidermal differentiation

Leiden epidermal skin models (LEMs) are cultured in vitro with a normal epidermal differentiation pattern. Early differentiation (e.g. keratin 1, keratin 10) is restricted to the suprabasal layers, whereas terminal differentiation (e.g. loricrin, involucrin) is found exclusively in the subcorneal granular layers of the epidermis.








Epidermal activation and stress-related proteins (e.g. keratin 16, keratin 17) are not present in LEMs, reflecting their normalized and non-activated state in vitro.









Basement membrane

Leiden epidermal skin models (LEMs) represent the human epidermis to the fullest, including functional basement membrane proteins (e.g. laminin 332, collagen type VII).











Healthy Leiden epidermal skin models (LEMs) are normally cultured air-exposed for 10 to 12 days. Application of compounds or treatments can be initiated during any culture phase relevant to the compound or treatment. For studying effects on in vitro human skin for over 2 weeks, we recommend the full thickness fibroblast-derived matrix (FDM) skin model, which lasts up to 20 weeks in vitro.



The Leiden epidermal skin model (LEM) is the perfect in vitro tool for a large variety of applications, including but not limited to:

  • Toxicity testing
  • Skin infection studies
  • Corrosivity testing
  • Irritation testing














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