Epidermal skin of only a few cm2 in size can be expanded several thousand times in cell cultures within 3 or 4 weeks and then be used to cover wounds. There have been reports on some patients with severe burns, whose skin was successfully replaced by autologous cultured epidermis in up to 50% of their body surface. The major drawbacks of this technique of skin replacement are the long culture period as well as the inferior mechanical stability and increased rate of wound contractures due to the lack of the dermal component. Since allogenic epidermal cell cultures are immunologically rejected, they are not suitable for the permanent coverage of wounds.