Organoids, also called mini-organs, are 3D tissue models grown from stem cells. They consist of various organ-specific cell types. For their production, embryonic stem cells, iPS cells or adult stem cells are used which, under suitable conditions, spontaneously form three dimensional structures with organ-like features that measure a few millimetres. The model system obtained in this way can be applied to study organ development and organ-specific diseases as well as new therapies and approaches to regenerative medicine.

In contrast to organs, organoids lack crucial structures such as blood vessels and immune cells. They are, however, highly suitable for the examination of processes such as the differentiation and self-organisation of cells as well as their cellular communication. Furthermore, the use of organoids holds great potential for the development of pharmaceutical products and tests. By using organoids, drugs can be tested in vitro on cultured cell models that are much more similar to human organs than previous 2D tissue or animal models. In the context of regenerative medicine, organoid cultures are considered promising to replace damaged tissue or even complete organs in the future. The hope is that cerebral organoids might cure the consequences of brain injuries, dementia development and strokes.

Besides the high expectations with regard to the research on organoids, a number of new ethical questions arises from this field of research such as the commercialisation of organoid technology, the factor that cell cultures reveal possible dispositions of the donor or the possibility that complex organoids might develop human sensations.