Wound care has become one of the first fields to see the benefit of a new technology: tissue engineering. Tissue engineering involves the development of new materials or devices capable of specific interactions with biological tissues. In wound care, these materials may be based entirely on naturally occurring tissues and cells, or may be materials that combine synthetics, usually polymers, with biological layers. Both wound dressings and skin substitutes are available. The complexity of the materials depends on the end uses. Generally, synthetics made from polymeric materials such as Tegaderm and Opsite are used as wound dressings over relatively simple and shallow wounds or as coverings over more complex dressings. Their function is one of protection from water loss, drying, and mechanical injury. More complex dressings vary from dermal replacements made of reconstituted collagen and chondroitan sulfate backed by a polymer layer such as Integra(R) to the complex Apligraftrade mark that contains collagen and seeded cells. This last is designed as a complete skin replacement or skin substitute. Ultimately, engineered skin will contain all of the components necessary to modulate healing and provide the desired response: a wound closed with limited scar tissue that retains all of the characteristics of natural skin.