Hyaluronic Acid Microneedles Loaded with Chinese Herbal Extracts as an Intradermal Delivery System for Hair Regeneration

leaf extract (PO-ex) was obtained using ethanol as a solvent, and then hyaluronic acid methacrylate/hyaluronic acid (HAMA/HA) hydrogel was loaded with PO-ex to prepare hyaluronic acid microneedles (PO-ex MN). The double cross-linked HAMA/HA provides sufficient mechanical strength to pierce the stratum corneum and deliver PO-ex into the dermis; PO-ex can effectively improve the environment for hair follicle cell proliferation by removing reactive oxygen free radicals; in addition, the self-repair reaction caused by microneedle mechanical stimulation activates the Wnt/β-catenin pathway associated with trauma repair and promotes hair follicle growth. PO-ex MN is a potential therapeutic strategy for the treatment of androgenic alopecia.