Organoid bioprinting: from cells to functional tissues

The biofabrication of complex human tissues to recapitulate organ-specific architecture and function requires a combination of engineering control and intrinsic self-assembly. Organoid bioprinting encompasses additive manufacturing approaches that can impart spatial control over the placement of organoids or organoid-forming cells to fabricate multicellular, 3D structures. In particular, bioprinting can be leveraged to control the spatial positioning of printed cells or tissues while maintaining the architecture and physiology of the constituent building blocks. In this Review, we discuss the emerging integration of bioprinting methods and tissue engineering. As bioprinting conventionally involves the patterning of a ‘material’ ink, we characterize cells and organoids as a living material and discuss how such a living material can be manipulated through biofabrication techniques. We focus on continuous and pick-and-place bioprinting methods in which spheroids, organoids or organoid-forming cells comprise the bioink. Additionally, we discuss organoid support baths into which inks are printed. Finally, we highlight how the combination of bioprinting approaches and organoid technology has the potential to improve engineered tissue models of development and disease.