Via ABC Online, a look at one strategy to build three-dimensional tissue structures: "It involves combining the expertise of biologists and chemical engineers, particularly where we mix cells and scaffolds together and implant them in the body where they grow and mature and develop into specific tissues. ... this essentially is an empty box into which we implant a blood vessel using microsurgery techniques. ... we use microsurgery to create this environment and we mix cells inside this chamber and we let them grow according to the specific environment that we can create. Now, currently we have been able to make breast tissue, fat, muscle, pancreas tissue that secretes insulin and we have also created thymus tissue, which may have an application in immunology. ... There is an artery in it that keeps this alive, but the heart cells are actually beating at their own rhythm."

Link: http://www.abc.net.au/worldtoday/content/2006/s1657710.htm