Scientists developed a technique for the large-scale preparation of hair follicle germs (HFGs), in vitro, using the self-organization of cells. Up to 5,000 HFGs prepared simultaneously were able to generate hair-follicle and shaft generation in mice, according to a paper published in the journal Biomaterials (Feb. 2018; 154:291–300).
“This simple method is very robust and promising,” said study author Junji Fukuda, PhD, professor of engineering at Yokohama National University in Yokohama, Japan, in a press release. “We hope that this technique will improve human hair regenerative therapy to treat hair loss such as androgenic alopecia. In fact, we have preliminary data that suggests human HFG formation using human keratinocytes and dermal papilla cells.”
The self-sorted HFGs, once transplanted on mice samples, resulted in spatially aligned hair follicle generation. They were encapsulated into a hydrogel during transplantation. Photo by Yokohama National University.
The procedure involved mixing mouse epidermal and mouse/human mesenchymal cells in suspension. Then, the cells were seeded in micro-wells of a custom-designed array plate. The culture period lasted three days. Cells formed a randomly distributed single cell aggregate and eventually, they separated from each other, displaying morphological features characteristic of HFGs.
The self-sorted HFGs (ssHFGS) were placed in an approximately 300-microwell array, called an “HFG chip.”
Then ssHFGs were encapsulated into a hydrogel and intracutaneously transplanted on the backs of mice.
Researchers reported the growth of black hair at both the back and scalp transplantation sites. According to the paper, the regenerated hair displayed the usual hair cycles of murine hair.
Notably, the HFG chip, made of silicone, provided an oxygen supply that was crucial to enabling both ssHFG formation and consequent hair shaft generation.
“The key for the mass production of HFGs was a choice of substrate materials for culture vessel,” said Dr. Fukuda. “We used oxygen-permeable dimethylpolysiloxane (PDMS) at the bottom of culture vessel, and it worked very well.”