Hair loss is a common disorder that affects men, women, and children due to aging, diseases, and medical treatments. Recent researches revealed that hair follicles can be regenerated by merging two aggregates composed of embryonic skin-derived epithelial cells and mesenchymal cells, and transplanting them intracutaneously. In this study, microfabrication approaches were employed for one-step preparation of a large number of epithelial and mesenchymal cell aggregates with a uniform diameter and spacing.

　In most previous studies, pellets of epithelial and mesenchymal cells were separately prepared and then merged them to fabricate a hair follicle for transplantation. In this study, two cell types were seeded as a mixed cell suspension on the poly(dimethylsiloxane) culture chip. Although these cells formed single aggregates in the wells at 3 days of culture, each cell type was spatially separated in the aggregates. This spontaneous separation of two cell types facilitated the preparation of a large number of cell aggregates. Hair follicles were regenerated from transplanted site after 18 days of transplantation. The regenerated hair follicles also showed the hair cycle through the rearrangement of follicular stem cells.