Platinum Nanozyme-Loaded Dissolving Microneedles Scavenge ROS and Promote Lineage Progression for Androgenetic Alopecia Treatment.

Androgenetic alopecia (AGA) is a prevalent issue affecting the physical and mental health of individuals but with fewer current treatments. Platinum nanozymes (PtNZs) are known for their excellent ability to reduce and modulate the high oxidative stress environment in AGA pathology. And microneedles are used to overcome the skin barrier due to the poor permeability of PtNZs. Herein, dissolving microneedles loaded with PtNZs (Pt-MNs) are designed and successfully induced hair regeneration in the AGA model. Pt-MNs possessed adequate mechanical strength to breach the skin barrier for effective PtNZs delivery. In vivo, PtNZs first reduced reactive oxygen species (ROS) to oxygen, which recovered the AGA pathological environment. And the oxygen then increased oxidative phosphorylation, promoting the differentiation of hair follicle stem cells to achieve hair regeneration. The group treated with Pt-MNs with a dosing frequency of once every three days achieved faster hair growth than the daily application of the positive drug minoxidil. Further safety experiments showed that the application of Pt-MNs locally opened temporary and recoverable skin channels, with no retention of Pt in major organs, indicating high safety. In conclusion, this study indicated the potential of Pt-MNs as an effective method for treating AGA.