Automation makes products and processes much less expensive, so it's only a matter of time and ingenuity before it's broadly applied to tissue engineering, as noted in this press release: "artificial skin is rare. [The] production is complex and involves a great deal of manual work. At this time, even the market's established international companies cannot produce more than 2,000 tiny skinpieces a month. ... In a multi-stage process, first small pieces of skin are sterilized. Then they are cut into small pieces, modified with specific enzymes, and isolated into two cell fractions, which are then propagated separately on cell culture surfaces. The next step in the process combines the two cell types into a two-layer model, with collagen added to the cells that are to form the flexible lower layer, or dermis. This gives the tissue natural elasticity. In a humid incubator kept at body temperature, it takes the cell fractions less than three weeks to grow together and form a finished skin model with a diameter of roughly one centimeter. The technique has already proven its use in practice, but until now it has been too expensive and complicated for mass production."