Integrating zinc/silicon dual ions with 3D-printed GelMA hydrogel promotes in situ hair follicle regeneration

The regeneration of hair follicles lost from injury or disease represents a major challenge in cutaneous regenerative medicine. In this study, we investigated the synergetic effects between zinc and silicon ions on dermal cells and screened the optimal concentration of ions for medical applications. We integrated zinc/silicon dual ions into gelatin methacryloyl (GelMA) to bioprint a scaffold and determined that its mechanical properties are suitable for biological treatment. Then, the scaffold was employed to treat mouse excisional model in order to promote in situ hair follicle regeneration. Our findings showed that GelMA-zinc/silicon-printed hydrogel can significantly activate hair follicle stem cells and enhance neovascularization. The beneficial effects of the scaffold were further confirmed by the growth of hairs in the center of wounds and the improvement in perfusion recovery. Taken together, the present study is the first to combine GelMA with zinc/silicon dual ions to bioprint in situ for treating excisional wound, and this approach may regulate hair follicle regeneration not only directly by impacting stem cells but also indirectly through promoting angiogenesis.