What Is an Organoid?

Fabian Theis says an organoid is a little piece of an organ grown in a dish. Cells taken out of a body can grow into small multicellular systems that connect and do things. He is not a trained biologist, and the first time he saw cells do that he was impressed.

People can put cells in a dish and grow mini brains, a set of neurons that start connecting and talking to each other. Those mini brains have been shown to compute. Heart cells can grow into little heart organoids that start beating, and collaborators of his have beating heart-cell clumps in a dish. The colon is a simpler system that works very well, and cancer systems exist too. When tissue is hard to acquire, as with some neurodegenerative diseases, the path is cells from the skin, turned into stem cells, then into little brains.

An organoid often has no immune system, and feeding it is its own problem. It is still much more than a cell line, which is one cell type.