Bioprinting of Hair Follicle Germs for Hair Regenerative Medicine

The study explored a scalable and automated method for preparing hair-inductive tissue grafts using bioprinting technology, aimed at treating hair loss. Researchers developed hair-follicle-germ-like grafts by placing collagen droplets containing mesenchymal and epithelial cells adjacent to each other. Over three days, these microgel beads contracted due to cell traction forces, enriching cell and collagen densities by over 10 times. When transplanted into mice, these hair microgels (HMGs) efficiently regenerated hair follicles and shafts, although the shafts mostly remained under the skin. To address this, microgels were printed onto surgical suture guides, which improved hair-shaft sprouting through the skin by controlling the orientation of the HMGs. This method showed promise for advancing hair regenerative medicine.