Stages of 3D-bioprinting, illustration. Three-dimensional (3D) bioprinting allows artificial construction of viable tissues and organs, for research or with the aim of transplantation. Several techniques are used, the most common are drop-based bioprinting (inkjet) and extrusion bioprinting. MRI and CT scans and software are used to generate a model of an organ or tissue. Stem cells or other cells are combined with growth factors, nutrients and appropriate matrix material to form bioink (red, green). Bioinks can be deposited in precise layers in a 3D printed biodegradable scaffold to produce a viable tissue or organ.