A proof of concept for the use of pluripotent cells in tissue engineering from ScienceDaily: scientists "report on their research to optimize the potential of [human embryonic stem cells or hESC cells] to generate complex, functional multilayer tissues, such as the oral mucosa and skin, and to understand how tissue fabrication is controlled and directed. ... [Researchers] used tissue engineering principles to produce complex oral-lining tissues that mimic many features of their counterparts found in the oral cavity. Making these tissues was a two-step process. With a combination of chemical signals and specialized surfaces on which these cells attach, an hESC cell line [was] directed toward two divergent cell populations. The first population comprises the surface layer (epithelial cells) of complex tissues, while the other is found beneath these cells (mesenchymal cells). ... The populations were then grown at an air-liquid interface to mimic their growth environment in the oral cavity. Within two weeks, tissues developed that shared many features in common with normal tissues that were constructed with mature cells that are the 'gold standard' of normal tissue generation in our lab."