Figure 1.

Schematic showing culture method and quality controls. (1) air‐exposed culture = 7–10 days. Viability control: Visual inspection (macroscopically) of attachment, >1 mm outgrowth on to dermis. (2) submerged culture = 7–10 days. Viability control: Microscopic inspection (phase contrast) > 50% confluent, adherent fibroblasts. (3) air‐exposed culture = 11–14 days. After the 3 week culture period, from each batch of skin substitute or gingiva substitute, 2 × 3 mm diameter biopsies were taken from the outgrowth region for (i) metabolic activity (MTT assay) and (ii) for characterization by histology and immunohistochemistry; potency by assessing soluble wound healing mediator release into culture medium (enzyme‐linked immunosorbent assay). For this extensive characterization study, further tissue samples were taken to assess epithelial differentiation and outgrowth