Organoids are organotypic multicellular constructs generated through self-renewal and self-organization of stem cells in a three-dimensional (3D) culture. They can recapitulate various aspects of their in vivo counterparts and thus serve as in vitro models to study early organ development and organ-specific disorders. Organoids have the potential to bridge clinical and preclinical trials and/or substitute animal models in preclinical trials. Cases exist where specific drugs that previously failed in clinical trials did not work on organoids although these drugs were shown to be efficacious in animal models. Animal models are traditionally the gold standard in vivo models and yet they are not always representative of results in humans.

Organoids-on-a-chip platforms leverage the integration of two different yet complementing approaches: organoids and organ-on-a-chip. These engineering platforms can meet emerging needs in organoid research and applications primarily for (1) automation of time-consuming, laborious, error-prone and low-throughput organoid protocols; (2) increased size uniformity and reproducibility of organoids; and (3) microenvironmental control. Potential applications include drug development, drug and toxicology screening, regenerative medicine, and disease modeling. The aim of this Method Collections is to curate and present state-of-the-art demonstrations and protocols addressing organoids-on-a-chip platforms as a practical guide to researchers interested in this nascent field.