Bioengineered Skin Tissue Construction

The epidermis was removed from pieces of surgical waste skin and discarded. The dermis was subjected to repeated freeze-thaw cycles followed by gamma irradiation, as described previously (Philippeos et al., 2018 (link)). De-epidermised dermis (DED) was placed in six-well microplate Millicell hanging inserts (Millipore). 5 × 10⁵ NHDF were resuspended in 30 μl complete DMEM and injected into the upper dermis using a 0.3 ml insulin syringe and needle (Becton Dickinson). NHDF-containing DED was cultured submerged in 3 ml/well complete DMEM for 24 h. 1 × 10⁶ keratinocytes (strain Km) were resuspended in 30 μl complete FAD, seeded onto the DED, and cultured in 2 ml/well complete FAD above the air–liquid interface for 2 weeks. The histological analysis is described in Supplementary Materials and Methods.