http://www.eurekalert.org/pub_releases/2005-11/uouh-uou111105.php...Like any printing process, organ printing requires ink, paper, and printer.
The "bio-ink" consists of cells taken from an organ, such as a blood vessel or heart valve. The "bio-paper" is Prestwich's hydrogel. The printer can be a standard ink-jet model, modified to use a solution of cells and liquid hydrogel instead of ink, or one designed for using bio-ink.
The cells and liquid hydrogel are placed in the printer cartridge and then dropped in three-dimensional, 1-microliter dots that form layers as the hydrogel solidifies. After many layers have been made, the cells fuse into tissue that forms 3-D structures. The hydrogel is removed, and new healthy tissue is left to implant into a damaged or diseased organ.
"We already have printed 3-D structures that mimic blood vessels," Forgacs said. [continued]