Muscle tissue produced with a 3D printer. San Diego startup Organovo has developed a bioprinting technique which allows it to create human tissue starting with any cell source. The printer deposits lines of cells closely together, where they are allowed to grow and interconnect until they form working muscle tissue.   Unlike other experimental approaches that utilize ink-jet printers to deposit cells, Organovo's technology enables cells to interact with each other the way they do in the body. How? They are packed tightly together, sandwiched, if you will, and incubated. This prompts them to cleave to each other and interchange chemical signals. When printed, the cells are grouped together in a paste that helps them grow, migrate, and align themselves properly. In the case of muscle cells, the way they orient themselves in the same direction allow for contractions of the tissue.   The company hopes to one day build entire organs for transplants. Because tissue is able to be built from a patient's own cells, the risk of rejection would be very low. via 8bitfuture: