Skin organoids as a new biological standard

Early in vitro models of human skin included two-dimensional cell cultures using keratinocytes and fibroblasts. Though cost-effective and simple to produce, these monolayers fail to recapitulate the skin’s three-dimensional structure. Further progress saw the layering of keratinocytes on top of fibroblasts, to create a three-dimensional ‘skin equivalent’. These could be increased in anatomical and functional relevance with the addition of other populations, such as dermal papilla cells to induce hair growth. However, hair growth in these in vitro constructs was often incomplete. Furthermore, these constructs lacked the diverse cell populations present within the human skin organ (Supplementary Table 1).