Polymeric membranes modulate human keratinocyte differentiation in specific epidermal layers

• CHT, PCL and CHT-PCL membranes were used for the engineering of epidermal systems.
• Specific membrane properties modulate and induce epidermal differentiation.
• Specific and fully differentiating epidermal strata were developed on membranes.
• Bioartificial epidermal membrane systems as in vitro models for testing of chemicals.

In vitro models of human bioengineered skin substitutes are an alternative to animal experimentation for testing the effects and toxicity of drugs, cosmetics and pollutants. For the first time specific and distinct human epidermal strata were engineered by using membranes and keratinocytes. To this purpose, biodegradable membranes of chitosan (CHT), polycaprolactone (PCL) and a polymeric blend of CHT-PCL were prepared by phase-inversion technique and characterized in order to evaluate their morphological, physico-chemical and mechanical properties. The capability of membranes to modulate keratinocyte differentiation inducing specific interactions in epidermal membrane systems was investigated. The overall results demonstrated that the membrane properties strongly influence the cell morpho-functional behaviour of human keratinocytes, modulating their terminal differentiation, with the creation of specific epidermal strata or a fully proliferative epidermal multilayer system. In particular, human keratinocytes adhered on CHT and CHT-PCL membranes, forming the structure of the epidermal top layers, such as the corneum and granulosum strata, characterized by withdrawal or reduction from the cell cycle and cell proliferation. On the PCL membrane, keratinocytes developed an epidermal basal lamina, with high proliferating cells that stratified and migrated over time to form a complete differentiating epidermal multilayer system.

AFM images of chitosan (CHT), chitosan-polycaprolactone (CHT-PCL) and polycaprolactone (PCL) membranes and LSCM micrographs of the corresponding epidermal layers realized by culturing human keratinocytes on the biodegradable membranes (cells are stained for actin, cytokeratin CK18, and counterstained for nuclei).Figure optionsDownload as PowerPoint slide