Tissue engineered skin: Apligraf, a bi-layered living skin equivalent. 
Driven by the need for a readily available, non-immunological tissue that possesses many of the characteristics of normal human skin, tissue-engineered skin has been developed.  For over a decade, laboratory grown or processed skin has been under investigation and, in some cases, available as an alternative to autologous grafts.  Apligraf, derived from neonatal foreskin and bovine type I collagen, is the first bi-layered living skin equivalent approved in the US and other countries for use in venous ulcers.  Apligraf is effective both in the treatment of refractory venous ulcers and for acute wounds such as surgical excision sites and split thickness donor sites.  Apligraf is safe and is not clinically rejected.  Its ultimate fate is not known, so it may well work to aid healing in a variety of ways including graft 'take' and as a stimulus for healing.