Organ printing: a novel tissue engineering paradigm

Abstract

Engineering new tissues, ideally from the patient's own body cells to prevent rejection by the immune system, is a rapidly growing field that rests on three pillars: cells, supporting structures (or scaffold) and stimulating biological environment. However the use of scaffolds has been associated with chronic inflammation and impaired tissue-remodeling and maturation. We introduce a novel automated rapid prototyping method (bioprinting) that allows engineering three-dimensional custom-shaped tissue and organ modules without the use of any scaffold, thus making the final construct fully biological, as well as structurally and functionally closer to native tissues. Conveniently prepared bio-ink units (multicellular spheroids or cylinders composed of single or several cell types) are delivered into the bio-paper (a hydrogel support material) by a special-purpose bio-printer. The delivery of the discrete bio-ink units is controlled by architectural software consistent with the geometry and composition of the desired organ module. Structure formation takes place by the post-printing fusion of the discrete units. We demonstrate the technology by detailing the construction of blood vessel substitutes. We also discuss undergoing translational and commercialization efforts with the help of our seed-stage company, Organovo, Inc., as well as the market opportunities afforded by the technology.