Hydrogel microneedles loaded with bFGF and PVP-modified iridium nanoparticles improve follicular microenvironment for androgenetic alopecia treatment

Abstract

Androgenetic alopecia (AGA), driven by excessive free radical generation within the hair follicle microenvironment and insufficient perifollicular microvascularization, remains a challenging condition due to the paucity of safe and effective treatment options. In this study, we presented the development of a gelatin methacrylate (GelMA)-based hydrogel-forming microneedles that encapsulated both basic fibroblast growth factor (bFGF) and polyvinylpyrrolidone (PVP)-modified iridium nanoparticles (IrNPs) (Ir/bFGF-MNs). Ir/bFGF-MNs possessed dual functions: alleviating oxidative stress and promoting angiogenesis. These combined effects contributed to the improvement of the perifollicular microenvironment, offering a promising approach for the treatment of AGA. Drawing upon the robust mechanical strength of Ir/bFGF-MNs, these devices penetrated the stratum corneum of the skin, facilitating the efficient delivery of bFGF and IrNPs to both the epidermis and dermis. This delivery system not only eliminated excessive reactive oxygen species (ROS) surrounding the hair follicle but also fostered angiogenesis. Simultaneously, it mechanically stimulated microvessel remodeling within the alopecic region, enhancing the periapical microenvironment. In comparison to clinical treatment with minoxidil for AGA, Ir/bFGF-MNs showed superior efficacy in promoting hair regeneration in AGA model mice. This approach not only enhanced hair quality to a greater extent but also required less frequent dosing and exhibited good biocompatibility. Therefore, Ir/bFGF-MNs is a more effective and convenient therapeutic strategy for AGA, which is informative and potentially applicable in the treatment of alopecia areata-related diseases.