Tissue-engineering researchers are working on tissue replacement projects for practically every body part — blood vessels and nerves, muscles, cartilage and bones, esophagus and trachea, pancreas, kidneys, liver, heart and even uterus.

A more immediate goal is to improve upon a multitude of smaller therapies: transplantable valves for ailing hearts, cell-and-gel preparations for crushed nerves, injections of skeletal muscle cells for urinary continence or new salivary gland tissue to rescue radiation patients from dry mouth.