A printable organ is an artificially constructed device designed for organ replacement, produced using 3D printing techniques. The primary purpose of printable organs is in transplantation. Research is currently being conducted on artificial heart, kidney, and liver structures, as well as other major organs. For more complicated organs, such as the heart, smaller constructs such as heart valves have also been the subject of research. Some printed organs have already reached clinical implementation, and primarily include hollow structures such as the bladder, as well as vascular structures such as urine tubes.
3D printing allows for the layer-by-layer construction of a particular organ structure to form a cell scaffold. This can be followed by the process of cell seeding, in which cells of interest are pipetted directly onto the scaffold structure. Additionally, the process of integrating cells into the printable material itself, instead of performing seeding afterwards, has been explored.
Modified inkjet printers have been used to produce three-dimensional biological tissue. Printer cartridges are filled with a suspension of living cells and a smart gel, the latter used for providing structure. Alternating patterns of the smart gel and living cells are printed using a standard print nozzle, with cells eventually fusing together to form tissue. When completed, the gel is cooled and washed away, leaving behind only live cells.
3D printing for producing a cellular construct was first introduced in 2003, when Thomas Boland of Clemson University patented the use of inkjet printing for cells. This process utilized a modified spotting system for the deposition of cells into organized 3D matrices placed on a substrate.
Since Boland's initial findings, the 3D printing of biological structures, also known as bioprinting, has been further developed to encompass the production of tissue and organ structures, as opposed to cell matrices. Additionally, more techniques for printing, such as extrusion bioprinting, have been researched and subsequently introduced as a means of production.