Here is an interesting application of guided tissue growth, that focuses on blood vessels. A wide range of work is under way on blood vessel engineering and control of growth, as the ability to incorporate blood vessels into tissue in specific ways is essential to realizing the most important goals of tissue engineering: "A team of engineers has created a bandage that in just one week not only encourages new blood vessel growth but helps guide that growth as well. ... The ability to pattern functional blood vessels at this scale in living tissue has not been demonstrated before. ... The team [calls] the bandage a 'microvascular stamp.' Unlike similar bandages developed to help spur blood vessel growth, the stamp contains living cells that encourage damaged tissue to grow according to the stamp's pattern. At nearly a centimeter across, the stamp is made of porous material that enables small molecules to sneak through in addition to the larger growth factors. The team tested it on a chicken embryo; when they removed it from the surface a week later, a network of new blood vessels appeared in the pattern of the stamp's channels. Future applications could include not only healing wounds, but also redirecting blood vessels to grow around blocked arteries, and even improving the delivery of cancer drugs by repairing blood vessels that feed cancerous cells."