Curcumin-zinc framework encapsulated microneedle patch for promoting hair growth

Hair loss is a growing esthetic condition driven by complex mechanisms that has numerous psycho-social implications. Conventional drug applications usually focus on a single treatment target, and the penetration depth restricts the post-delivery effect. Method: We fabricated a curcumin-zinc framework (ZnMOF) encapsulated gamma-polyglutamic acid (γ-PGA) microneedle patch (ZnMOF-MN) as a multifunctional biosafe transdermal drug delivery system. ZnMOF was characterized with the field emission scanning electron microscope (FE-SEM), dynamic light scattering (DLS), elemental mapping, and X-ray diffraction (XRD). The topographical and hygroscopic features of ZnMOF-MN were characterized with SEM. The in vitro ZnMOF release profile and the in vivo penetration of ZnMOF-MN were also evaluated. The anti-oxidant, anti-apoptosis, and antiandrogen effects of ZnMOF solution and ZnMOF-MN extract were studied on mouse dermal papilla cells (DPCs). Two animal models (in C57BL/6 mice), including androgenic alopecia (AGA) model and wound healing model, were used to identify the therapeutic effect of ZnMOF-MN on hair regrowth and wound healing in vivo. Hair follicles, surrounding vessels (CD31+), and proliferating cells (Ki67+) were evaluated by histological staining. Results: ZnMOF crystals were cone-shaped nanoparticles with a size distribution of 424.9 ± 59.01 nm. ZnMOF-MN patch can create temporary holes in the skin to directly and evenly deliver bioactive ZnMOF particles to the targeted depth and achieve a steady and sustained release of Zn²⁺ and curcumin. In vitro, ZnMOF significantly improved the viability of DPCs against the excess reactive oxygen species (ROS) and inhibited the apoptosis induced by zinc deficiency. In addition, it also reversed the inhibitory effects of dihydrotestosterone (DHT) infiltration. Moreover, the ZnMOF-MN treatment has been proved to accelerate wound healing and increase hair follicles in wound healing models, and improved the hair regrowth in AGA animal models. Enhanced capillary density and cell proliferation observed in the CD31+ and Ki67+ staining of ZnMOF-MN group in both animal models also suggested that ZnMOF can facilitate angiogenesis and promote cell proliferation in the skin, respectively. Conclusion: The ZnMOF-MN treatment is a comprehensive solution with excellent therapeutic efficacy and patient-friendly features for promoting hair growth under various clinical conditions.